综合点评

本场考试继续延续一场多题的情况，共有ABCD四套题目。其中文章的题材涉及生物，天文，社科，历史类等，涵盖的范围较广。本场考试阅读加试比较普遍，涉及的词汇题题目个数较多，同时有重复前些年文章的情况。

Passage one

学科分类

题目

社会科学类

The Early History of Motion Pictures

内容回忆

本篇重复了很久之前的一篇原题，讲了电影早期的发展史，从为了解决一个赌约关于马蹄是否同时离地，引出了motion picture 摄影机的发明，从小规模投影发展到后来的大规模投影，一直到现在的mass media。关于背景知识，可以参考OG第2篇early cinema，里边有涉及到一些概念，比如phonograph, Kinetoscope parlors 是重复的。

参考阅读

考题：The Early History of Motion Pictures

Motion pictures and television are possible because of two quirks of the human perceptual system: the phi phenomenon and persistence of vision. The phi phenomenon refers to what happens when a person sees one light sources go out while another one close to the original is illuminated. To our eyes, it looks like the light moves from one place to another. In persistence of vision, our eyes continue to see an image for a spit second after the image has disappeared from view. First observed by the ancient Greeks, persistence of vision became more widely known in 1824 when Peter Roget(who also developed the thesaurus) demonstrated that human begins retain an image of an object for about one-tenth of a second after the object is taken from view. Following Roget’s pronouncement, a host of toys that depended on this principle sprang up in Europe. Bearing fanciful manes (the Thaumatrope, the Praxinoscope), these devices made a series of hand-drawn pictures appear to move.

Before long, several people realized that a series of still photographs on celluloid film could be used instead of hand drawing. In 1878 a colorful Englishman later turned American. Edward Muybridge, attempted to settle a $25.000 bet over whether the four feet of a galloping horse ever simultaneously left the ground. He arranged a series of 24 cameras alongside a racetrack to photograph a galloping horse. Rapidly viewing the series of pictures produced an effect much like that of a motion picture. Muybirdge’s technique not only settled the bet (the feet did leave the ground simultaneously at certain instances) but also photography. Instead of 24 cameras talking one pictures in rapid order, it was Thomas Edison and his assistant, William Dickson, who finally developed what might have been the first practical motion-picture camera and viewing device, Edison was apparently trying to provide a visual counterpart to his recently invented phonograph. When his early efforts did not work out, he turned the project over his assistant. Using flexible film, Dickson solved the vexing problem of how to move the film rapidly through the camera by perforating its edge with tiny holes and pulling it along by means of sprockets, projections on a wheel that fit into the holes of the film in 1889 Dickson had perfected a machine called the Kinetoscope and even starred in a brief film demonstrating how it worked.

These early efforts in the Edison lab were not directed at projecting movies to large crowds. Still influenced by the success of his phonograph, Edison thought a similar device could make a money by showing brief films to one person at a time for a penny a look. Edison built a special studio to produce films for his new invention, and by 1894, Kinetoscope parlors were spring up in major cities. The long-range commercial potential of his invention was lost on Edison. He reasoned that the real money would be made by selling his peep-show machine. If a large number of people were shown the film at the same time, fewer machines would be needed. Developments in Europe proved Edison wrong as inventors there devised large-screen projection devices. Faced with competition, Edison perfected the Vitascope and unveiled it in New York City in 1896.

Early monies were simple snippets of action—acrobats tumbling, horse running, jugglers juggling, and so on. Eventually, the novelty wore off and films became less of an attraction. Public interest was soon rekindled when early filmmakers discovered that movies could be used to tell story. In France, Alice Guy-Blachè produced The Cabbage Fairy, a one-minute film about a fairy who produces children in a Cabbage patch, and exhibited it at the Paris International Exhibition in 1896. Guy-Blachè went on to found her own studio in America. Better known is the work of a fellow French filmmaker and magician, Georges Méliès. In 1902 Méliès produced a science-fiction film that was the great-great-grandfather of Star Wars and Star Trek; it was called A Trip to the Moon.

Passage two

学科分类

题目

社会科学类

Domestication

内容回忆

学者们在探索domestication的起因，有理论认为人口数量增加带来的压力，人们不得不通过domestication来增加食物供给；还有理论认为是天气变化或者饥荒导致的。

参考阅读

考题：Domestication

About 10,000 years ago, after nearly 4 million years of human evolution and over 100,000 years of successful foraging for food, human beings, although isolated, nearly simultaneously developed a subsistence strategy that involved domesticated plants and animals. Why? Some scholars seek a single, universal explanation that would be valid for all cases of domestication. Thus, it has been argued that domestication is the outcome of population pressure, as the increasing hunting-and-gathering human population overwhelmed the existing food resources. Others point to climate change or famine, as the post-glacial climate got drier. Increasing archaeological research has made it clear, however, that the evidence in favor of any single-cause, universally applicable explanation is not strong.

Some scholars have proposed universally applicable explanations that take several different phenomena into account. One such explanation, called the broad-spectrum foraging argument (the argument that humans employed a subsistence strategy based on obtaining a wide range of plants and animals), is based on a reconstruction of the environmental situation that followed the retreat of the most recent glaciers. The very large animals of the Ice Age began to die out and were replaced by increased numbers of smaller animals. As sea levels rose to cover the continental shelves, fish and shellfish became more plentiful in the warmer, shallower waters. The effects on plants were equally dramatic, as forests and woodlands expanded into new areas. Consequently, scholars argue, people had to change their diets from big-game hunting to broad-spectrum foraging for plants and animals by hunting, fishing, and gathering. This broadening of the economy is said to have led to a more secure subsistence base, the emergence of sedentary communities, and a growth in population. In turn, population growth pressured the resource base of the area, and people were forced to eat so-called third-choice foods, particularly wild grain, which was difficult to harvest and process but which responded to human efforts to increase yields.Although the broad-spectrum foraging argument seems to describe plant domestication in the New World, the most recent evidence from ancient southwestern Asia does not support it. There is also evidence for the development of broad-spectrum foraging in Europe, but domestication did not follow. Rather, domesticated crops were brought into Europe by people from southwestern Asia—where the broad-spectrum revolution had not occurred.

A very different argument comes from Barbara Bender, who argues that before farming began, there was competition between local groups to achieve dominance over each other through feasting and the expenditure of resources on ritual and exchange, engaging in a kind of prehistoric arms race. To meet increasing demands for food and other resources, land use was intensified, and the development of food production followed.

This argument clearly emphasizes social factors, rather than environmental or technical factors, and takes a localized, regional approach. It is supported by ethnography (direct and systematic observations of a human culture) concerning competitive exchange activities, such as the potlatch (traditional celebrations in which groups gather and give gifts) of the indigenous inhabitants of the northwest coast of North America. These people were foragers in a rich environment that enabled them to settle in relatively permanent villages without farming or herding. Competition among neighboring groups led to ever-more elaborate forms of competitive exchange, with increasingly large amounts of food and other goods being given away at each subsequent potlatch. As suggestive as Bender’s argument is, however, it is difficult to find evidence for competitive feasting in archaeological remains.

Recently, archaeologists have avoided grand theories claiming that a single, universal process was responsible for domestication wherever it occurred. Many prefer to take a regional approach, searching for causes particular to one area that may or may not apply to other areas. Currently, the most powerful explanations seem to be multiple-strand theories that consider the combined local effects of climate, environment, population, technology, social organization, and diet on the emergence of domestication.

Passage three

学科分类

题目

生物科学类

coral reef

内容回忆

本篇文章讲了珊瑚礁的构造及发展过程，可以参考47-2 coral reef 的一些背景知识以及涉及到的一些专业知识。

参考阅读

参考：47-2 coral reef

An important environment that is more or less totally restricted to the intertropical zone is the coral reef. Coral reefs are found where the ocean water temperature is not less than 21 °C, where there is a firm substratum, and where the seawater is not rendered too dark by excessive amounts of river-borne sediment. They will not grow in very deep water, so a platform within 30 to 40 meters of the surface is a necessary prerequisite for their development. Their physical structure is dominated by the skeletons of corals, which are carnivorous animals living off zooplankton. However, in addition to corals there are enormous quantities of algae, some calcareous, which help to build the reefs. The size of reefs is variable. Some atolls are very large-Kwajelein in the Marshall Islands of the South Pacific is 120 kilometers long and as much as 24 kilometers across-but most are very much smaller, and rise only a few meters above the water. The 2,000 kilometer complex of reefs known as the Great Barrier Reef, which forms a gigantic natural breakwater off the northeast coast of Australia, is by far the greatest coral structure on Earth.

Coral reefs have fascinated scientists for almost 200 years, and some of the most pertinent observations of them were made in the 1830s by Charles Darwin on the voyage of the Beagle. He recognized that there were three major kinds: fringing reefs, barrier reefs, and atolls; and he saw that they were related to each other in a logical and gradational sequence. A fringing reef is one that lies close to the shore of some continent or island. Its surface forms an uneven and rather rough platform around the coast, about the level of low water, and its outer edge slopes downwards into the sea. Between the fringing reef and the land there is sometimes a small channel or lagoon. When the lagoon is wide and deep and the reef lies at some distance from the shore and rises from deep water it is called a barrier reef. An atoll is a reef in the form of a ring or horseshoe with a lagoon in the center.

Darwin's theory was that the succession from one coral reef type to another could be achieved by the upward growth of coral from a sinking platform, and that there would be a progression from a fringing reef, through the barrier reef stage until, with the disappearance through subsidence (sinking) of the central island, only a reef-enclosed lagoon or atoll would survive. A long time after Darwin put forward this theory, some deep boreholes were drilled in the Pacific atolls in the 1950s. The drill holes passed through more than a thousand meters of coral before reaching the rock substratum of the ocean floor, and indicated that the coral had been growing upward for tens of millions of years as Earth's crust subsided at a rate of between 15 and 51 meters per million years. Darwin s theory was therefore proved basically correct. There are some submarine islands called guyots and seamounts, in which subsidence associated with sea-floor spreading has been too speedy for coral growth to keep up.

Like mangrove swamps, coral reefs are extremely important habitats. Their diversity of coral genera is greatest in the warm waters of the Indian Ocean and the western Pacific. Indeed, they have been called the marine version of the tropical rain forest, rivaling their terrestrial counterparts in both richness of species and biological productivity. They also have significance because they provide coastal protection, opportunities for recreation, and are potential sources of substances like medicinal drugs. At present they are coming under a variety of threats, of which two of the most important are dredging and the effects of increased siltation brought about by accelerated erosion from neighboring land areas.

Passage Four

学科分类

题目

社科类

生命的起源

内容回忆

版本一：地球早上大气成分及生物 早上甲烷气体与二氧化碳占关键影响力，沒有氧气。由于拥有会植物光合作用的病菌，造成了很多氧气，耗费二氧化碳，出示臭氧层，为现如今新生物钟出示必需自然环境。 　　

版本二：讲地球开始如何造成生物的。大约有几个方面，是太阳光那时候不足热，地球那时候气体构成像活火山的，关键靠二种气体加溫度，好像一种是二氧化碳另一种是m开始的，那类气体构成不宜性命也没有什么氧，那时候的organism有非常大功效，开展植物光合作用造成氧气消化吸收二氧化碳，二氧化碳也有一部分被迁移成非汽态的，那样就产生了之后的空气构成，氧气能够产生臭氧层，维护生物不会受到紫外线辐射，这方面提及了火花等别的星体就沒有臭氧层或是活性氧不足，总之那时候生物都去海中了由于水能够消化吸收紫外线辐射维护他们 　

参考阅读

考题：Earth’s Atmosphere

Earth’s atmosphere has changed through time. Compared to the Sun, whose composition is representative of the raw materials from which Earth and other planets in our solar system formed, Earth contains less of some volatile elements, such as nitrogen, argon, hydrogen, and helium. These elements were lost when the envelope of gases, or primary atmosphere, that surrounded early Earth was stripped away by the solar wind or by meteorite impacts, or both. Little by little, the planet generated a new, secondary atmosphere by volcanic outgassing of volatile materials from its interior.

Volcanic outgassing continues to be the main process by which volatile materials are released from Earth – although it is now going on at a much slower rate. The main chemical constituent of volcanic gases (as much as 97 percent of volume) is water vapor, with varying amounts of nitrogen, carbon dioxide, and other gases. In fact, the total volume of volcanic gases released over the past 4 billion years or so is believed to account for the present composition of the atmosphere with one important exception: oxygen. Earth had virtually no oxygen in its atmosphere more than 4 billion years ago, but the atmosphere is now approximately 21 percent oxygen.

Traces of oxygen were probably generated in the early atmosphere by the breakdown of water molecules into oxygen and hydrogen by ultraviolet light (a process called photodissociation). Although this is an important process, it cannot begin to account for the present high levels of oxygen in the atmosphere. Almost all of the free oxygen now in the atmosphere originated through photosynthesis, the process whereby plants use light energy to induce carbon dioxide to react with water, producing carbohydrates and oxygen.

Oxygen is a very reactive chemical, so at first most of the free oxygen produced by photosynthesis was combined with iron in ocean water to form iron oxide-bearing minerals. The evidence of the gradual transition from oxygen-poor to oxygen-rich water is preserved in seafloor sediments. The minerals in seafloor sedimentary rocks that are more than about 2.5 billion years old contain reduced (oxygen-poor) iron compounds. In rocks that are less than 1.8 billion years old, oxidized (oxygen-rich) compounds predominate. The sediments that were precipitated during the transition contain alternating bands of red (oxidized iron) and black (reduced iron) minerals. These rocks are called banded-iron formations. Because ocean water is in constant contact with the atmosphere, and the two systems function together in a state of dynamic equilibrium, the transition from an oxygen-poor to an oxygen-rich atmosphere also must have occurred during this period.

Along with the buildup of molecular oxygen (O2) came an eventual increase in ozone (O3) levels in the atmosphere. Because ozone filters out harmful ultraviolet radiation, this made it possible for life to flourish in shallow water and finally on land. This critical state in the evolution of the atmosphere was reached between 1100 and 542 million years ago. Interestingly, the fossil record shows an explosion of life forms 542 million years ago.

Oxygen has continued to play a key role in the evolution and form of life. Over the last 200 million years, the concentration of oxygen has risen from 10 percent to as much as 25 percent of the atmosphere, before setting (probably not permanently) at its current value of 21 percent. This increase has benefited mammals, which are voracious oxygen consumers. Not only do we require oxygen to fuel our high-energy, warm-blooded metabolism, our unique reproductive system demands even more. An expectant mother’s used (venous) blood must still have enough oxygen in it to diffuse through the placenta into her unborn child’s bloodstream. It would be very difficult for any mammal species to survive in an atmosphere of only 10 percent oxygen.

Geologists cannot yet be certain why the atmospheric oxygen levels increased, but they have a hypothesis. First photosynthesis is only one part of the oxygen cycle. The cycle is completed by decomposition, in which organic carbon combines with oxygen and forms carbon dioxide. But if organic matter is buried as sediment before it fully decomposes, its carbon is no longer available to react with the free oxygen. Thus there will be a net accumulation of carbon in sediments and of oxygen in the atmosphere.

Passage Five

学科分类

题目

社会科学类

尼罗河影响农业

内容回忆

本篇文章讲到尼罗河对沿岸农业和人口的影响，尼罗河周边的农业方式(农业)

参考阅读

21-2 The Origins of Agriculture

  How did it come about that farming developed independently in a number of world centers (the Southeast Asian mainland, Southwest Asia, Central America, lowland and highland South America, and equatorial Africa) at more or less the same time? Agriculture developed slowly among populations that had an extensive knowledge of plants and animals. Changing from hunting and gathering to agriculture had no immediate advantages. To start with, it forced the population to abandon the nomad's life and become sedentary, to develop methods of storage and, often, systems of irrigation. While hunter-gatherers always had the option of moving elsewhere when the resources were exhausted, this became more difficult with farming. Furthermore, as the archaeological record shows, the state of health of agriculturalists was worse than that of their contemporary hunter-gatherers.

  Traditionally, it was believed that the transition to agriculture was the result of a worldwide population crisis. It was argued that once hunter-gatherers had occupied the whole world, the population started to grow everywhere and food became scarce; agriculture would have been a solution to this problem. We know, however, that contemporary hunter-gatherer societies control their population in a variety of ways. The idea of a world population crisis is therefore unlikely, although population pressure might have arisen in some areas.

Climatic changes at the end of the glacial period 13,000 years ago have been proposed to account for the emergence of farming. The temperature increased dramatically in a short period of time (years rather than centuries), allowing for a growth of the hunting-gathering population due to the abundance of resources. There were, however, fluctuations in the climatic conditions, with the consequences that wet conditions were followed by dry ones, so that the availability of plants and animals oscillated brusquely.

It would appear that the instability of the climatic conditions led populations that had originally been nomadic to settle down and develop a sedentary style of life, which led in turn to population growth and to the need to increase the amount of food available. Farming originated in these conditions. Later on, it became very difficult to change because of the significant expansion of these populations. It could be argued, however, that these conditions are not sufficient to explain the origins of agriculture. Earth had experienced previous periods of climatic change, and yet agriculture had not been developed.

   It is archaeologist Steven Mithen's thesis, brilliantly developed in his book The Prehistory of the Mind (1996), that approximately 40,000 years ago the human mind developed cognitive fluidity, that is, the integration of the specializations of the mind: technical, natural history (geared to understanding the behavior and distribution of natural resources), social intelligence, and the linguistic capacity. Cognitive fluidity explains the appearance of art, religion, and sophisticated speech. Once humans possessed such a mind, they were able to find an imaginative solution to a situation of severe economic crisis such as the farming dilemma described earlier. Mithen proposes the existence of four mental elements to account for the emergence of farming: (1) the ability to develop tools that could be used intensively to harvest and process plant resources; (2) the tendency to use plants and animals as the medium to acquire social prestige and power; (3) the tendency to develop "social relationships" with animals structurally similar to those developed with people—specifically, the ability to think of animals as people (anthropomorphism) and of people as animals (totemism); and (4) the tendency to manipulate plants and animals.

   The fact that some societies domesticated animals and plants, discovered the use of metal tools, became literate, and developed a state should not make us forget that others developed pastoralism or horticulture (vegetable gardening) but remained illiterate and at low levels of productivity; a few entered the modern period as hunting and gathering societies. It is anthropologically important to inquire into the conditions that made some societies adopt agriculture while others remained hunter-gatherers or horticulturalists. However, it should be kept in mind that many societies that knew of agriculture more or less consciously avoided it. Whether Mithen's explanation is satisfactory is open to contention, and some authors have recently emphasized the importance of other factors.

Passage Six

学科分类

题目

自然科学

Modification of weather

内容回忆

多年来人们一直努力改变天气。是发现一战期间，降雨增多(可能与武器使用有关)，美国农业部开始试验。后来 1946 年，有个员工发现干冰能让 supercooled water becomesnow particles.文章给 supercool 下了定义就是低于零度但是还没有结冰。于是人们开始用 dry ice和 silver iodide来进行人工降雨。其原理就是 dry ice makes the moisture freeze into ice particles and thesurrounding moisture freeze around it.也就是为降雨提供了凝结核。后来文章说有人担心这样下去会使地面水体的含银量增高，但是调查并没有显示这个说法。这种 cloud seeding 办法继续发展，用别的物质替代干冰。但是很多人 concern这种办法，会对 local 的环境带来影响，但是并无定论。

参考阅读

考题：The Climate of Japan

At the most general level, two major climatic forces determine Japan’s weather. Prevailing westerly winds move across Eurasia, sweep over the Japanese islands, and continue eastward across the Pacific Ocean. In addition, great cyclonic airflows (masses of rapidly circulating air) that arise over the western equatorial Pacific move in a wheel-like fashion northeastward across Japan and nearby regions. During winter months heavy masses of cold air from Siberia dominate the weather around Japan. Persistent cold winds skim across the Sea of Japan from the northwest, picking up moisture that they deposit as several feet of snow on the western side of the mountain ranges on Honshu Island. As the cold air drops its moisture, it flows over high ridges and down eastern slopes to bring cold, relatively dry weather to valleys and coastal plains and cities.

In spring the Siberian air mass warms and loses density, enabling atmosphere currents over the Pacific to steer warmer air into northeast Asia. This warm, moisture-laden air covers most of southern Japan during June and July. The resulting late spring rains then give way to a drier summer that is sufficiently hot and muggy, despite the island chain’s northerly latitude, to allow widespread rice cultivation.

Summer heat is followed by the highly unpredictable autumn rains that accompany the violent tropical windstorm known as typhoons. These cyclonic storms originate over the western Pacific and travel in great clockwise arcs, initially heading west toward the Philippines and southern China, curving northward later in the season. Cold weather drives these storms eastward across Japan through early autumn revitalizing Siberian air mass and ushering in a new annual weather cycle.

This yearly cycle has played a key role in shaping Japanese civilization. It has assured the islands ample precipitation, ranging irregularly from more than 200 centimeters annually in parts of the southwest to about 100 in the northeast and averaging 180 for the country as a whole. The moisture enables the islands to support uncommonly lush forest cover, but the combination of precipitous slopes and heavy rainfall also gives the islands one of the world’s highest rates of natural erosion, intensified by both human activity and the natural shocks of earthquakes and volcanism. These factors have given Japan its wealth of sedimentary basins, but they have also made mountainsides extremely susceptible to erosion and landslides and hence generally unsuitable for agricultural manipulation.

The island chain’s mountainous backbone and great length from north to south produce climatic diversity that has contributed to regional differences. Generally sunny winters along the Pacific seaboard have made habitation there relatively pleasant. Along the Sea or Japan, on the other hand, cold, snowy winters have discouraged settlement. Furthermore, although annual precipitation is high in that region, much of it comes as snow and rushes to the sea as spring runoff, leaving little moisture for farming.

Summer weather patterns in northern Honshu, and especially along the Sea of Japan, have also discouraged agriculture. The area is subject to the yamase effect, when cool air from the north sometimes lowers temperatures sharply and damages farm production. The impact of this effect has been especially great on rice cultivation because, if it is to grow well, the rice grown in Japan requires a mean summer temperature of 20°centigrade or higher. A drop of 2°—3°can lead to a 30—50 percent drop in rice yield, and the yamase effect is capable of exceeding that level. This yamase effect does not, however, extend very far south, where most precipitation comes in the form of rain and the bulk of it in spring, summer, and fall, when most useful for cultivation. Even the autumn typhoons, which deposit most of their moisture along the southern seaboard, are beneficial because they promote the start of the winter crops that for centuries have been grown in southern Japan.

In short, for the past two millennia, the climate in general and patterns of precipitation in particular have encouraged the Japanese to cluster their settlements along the southern coast, most densely along the sheltered Inland Sea, moving into the northeast. There the limits that topography imposed on production have been tightened by climate, with the result that agricultural output has been more modest and less reliable, making the risk of crop failure and hardship commensurately greater.

Passage Seven

学科分类

题目

生物学

Distribution of Plants and Animals

内容回忆

地球上植物之间的相似性要远大于动物。原因一是植物很早以前就开始大范围传播，在大陆板块分开之前就分布到各处，而动物出现得较晚；原因二是动物曾经历了多次大毁灭，且之后出现的新物种代替了旧物种与原来很不相同，而植物则很长寿；原因三是动物群不如植物群一样分散广，每一个地方都有特定的动物种类，只有当大陆相连接的时候，动物才能进行传播。植物群分散比较广，并且即便是由于大陆漂移，植物也可以越过海洋进行种子的传播。所以人们能看到各个地方相似的植物群出现。之后转折，在亚洲和非洲两地的动物相似性却很高，是因为当时一度亚非板块相连。

参考阅读

31-1 Speciation in Geographically Isolated Populations

Evolutionary biologists believe that speciation, the formation of a new species, often begins when some kind of physical barrier arises and divides a population of a single species into separate subpopulations. Physical separation between subpopulations promotes the formation of new species because once the members of one subpopulation can no longer mate with members of another subpopulation, they cannot exchange variant genes that arise in one of the subpopulations. In the absence of gene flow between the subpopulations, genetic differences between the groups begin to accumulate. Eventually the subpopulations become so genetically distinct that they cannot interbreed even if the physical barriers between them were removed. At this point the subpopulations have evolved into distinct species. This route to speciation is known as allopatry (“allo-” means “different”, and “patria” means “homeland”).

Allopatric speciation may be the main speciation route. This should not be surprising, since allopatry is pretty common. In general, the subpopulations of most species are separated from each other by some measurable distance. So even under normal situations the gene flow among the subpopulations is more of an intermittent trickle than a steady stream. In addition, barriers can rapidly arise and shut off the trickle. For example, in the 1800s a monstrous earthquake changed the course of the Mississippi River, a large river flowing in the central part of the United States of America. The change separated populations of insects now living along opposite shore, completely cutting off gene flow between them.

Geographic isolation also can proceed slowly, over great spans of time. We find evidence of such extended events in the fossil record, which affords glimpses into the breakup of formerly continuous environments. For example, during past ice ages, glaciers advanced down through North America and Europe and gradually cut off parts of populations from one another. When the glaciers retreated, the separated populations of plants and animals came into contact again. Some groups that had descended from the same parent population were no longer reproductively compatible— they had evolved into separate species. In other groups, however, genetic divergences had not proceeded so far, and the descendants could still interbreed— for them, reproductive isolation was not completed, and so speciation had not occurred.

Allopatric speciation can also be brought by the imperceptibly slow but colossal movements of the tectonic plates that make up Earth’s surface. About 5 million years ago such geologic movements created the land bridge between North America and South America that we call the Isthmus of Panama. The formation of the isthmus had important consequences for global patterns of ocean water flow. While previously the gap between the continents had allowed a free flow of water, now the isthmus presented a barrier that divided the Atlantic Ocean from the Pacific Ocean. This division set the stage for allopatric speciation among populations of fishes and other marine species.

In the 1980s, John Graves studied two populations of closely related fishes, one population from the Atlantic side of isthmus, the other from the Pacific side. He compared four enzymes found in the muscles of each population. Graves found that all four Pacific enzymes function better at lower temperatures than the four Atlantic versions of the same enzymes. This is significant because Pacific seawater is typically 2 to 3 degrees cooler than seawater on the Atlantic side of isthmus. Analysis by gel electrophoresis revealed slight differences in amino acid sequence of the enzymes of two of the four pairs. This is significant because the amino acid sequence of an enzyme is determined by genes.

Graves drew two conclusions from these observations. First, at least some of the observed differences between the enzymes of the Atlantic and Pacific fish populations were not random but were the result of evolutionary adaptation. Second, it appears that closely related populations of fishes on both sides of the isthmus are starting to genetically diverge from each other. Because Graves’s study of geographically isolated populations of isthmus fishes offers a glimpse of the beginning of a process of gradual accumulation of mutations that are neutral or adaptive, divergences here might be evidence of allopatric speciation in process.

Passage Eight

学科分类

题目

社会科学

Chinese ancient art

内容回忆

讲述了中国古代的艺术形式，比如茶叶，瓷器，翡翠，书法，丝绸等

参考阅读

27-1 Crafts in the Ancient Near East

Some of the earliest human civilizations arose in southern Mesopotamia, in what is now southern Iraq, in the fourth millennium B.C.E. In the second half of the millennium, in the south around the city of Uruk, there was an enormous escalation in the area occupied by permanent settlements. A large part of that increase took place in Uruk itself, which became a real urban center surrounded by a set of secondary settlements. While population estimates are notoriously unreliable, scholars assume that Uruk inhabitants were able to support themselves from the agricultural production of the field surrounding the city, which could be reached with a daily commute. But Uruk’s dominant size in the entire region, far surpassing that of other settlements, indicates that it was a regional center and a true city. Indeed, it was the first city in human history.

The vast majority of its population remained active in agriculture, even those people living within the city itself. But a small segment of the urban society started to specialize in nonagricultural tasks as a result of the city’s role as a regional center. Within the productive sector, there was a growth of a variety of specialist craftspeople. Early in the Uruk period, the use of undecorated utilitarian pottery was probably the result of specialized mass production. In an early fourth-millennium level of the Eanna archaeological site at Uruk, a pottery style appears that is most characteristic of this process, the so-called beveled-rim bowl. It is a rather shallow bowl that was crudely made in a mold; hence, in only a limited number of standard sizes. For some unknown reason, many were discarded, often still intact, and thousands have been found all over the Near East. The beveled-rim bowl is one of the most telling diagnostic finds for identifying an Uruk-period site. Of importance is the fact that it was produced rapidly in large amounts, most likely by specialists in a central location.

A variety of documentation indicates that certain goods, once made by a family member as one of many duties, were later made by skilled artisans. Certain images depict groups of people, most likely women, involved in weaving textiles, an activity we know from later third-millennium texts to have been vital in the economy and to have been centrally administered. Also, a specialized metal-producing workshop may have been excavated in a small area at Uruk. It contained a number of channels lined by a sequence of holes, about 50 centimeters deep, all showing burn marks and filled with ashes. This has been interpreted as the remains of a workshop where molten metal was scooped up from the channel and poured into molds in the holes. Some type of mass production by specialists were involved here.

Objects themselves suggest that they were the work of skilled professionals. In the late Uruk period(3500-3100 B.C.E.), there first appeared a type of object that remained characteristic for Mesopotamia throughout its entire history: the cylinder seal. This was a small cylinder, usually no more than 3 centimeters high and 2 centimeters in diameter, of shell, bone, faience (a glassy type of stoneware), or various types of stones, on which a scene was carved into the surface. When rolled over a soft material----primarily the clay of bullae (round seals), tablets, or clay lumps attached to boxes, jars, or door bolts----the scene would appear in relief, easily legible. The technological knowledge needed to carved it was far superior to that for stamp seals, which had happened in the early Neolithic period (approximately 10,000-5000 B.C.E.). From the first appearance of cylinder seals, the carved scenes could be highly elaborate and refined, indicating the work of specialist stone-cutters. Similarly, the late Uruk period shows the first monumental art, relief, and statuary in the round, made with a degree of mastery that only a professional could have produced.

Passage Nine

学科分类

题目

生物科学类

太平洋岛上的蜥蜴

内容回忆

介绍了一种蜥蜴，分布广泛，主要在Hawaii附近的太平洋小岛上，主要特性有small，颜色暗(less sleek啥，和另外一个lizard有对比，一二题都是这里)，生活在大型树木上，大木头可以带着它们漂流到岛。然后探究了岛上有这个蜥蜴的起源，蜥厉害的一点是可以无性繁殖，就是female自己繁殖不需要mating，好处是单一物种可以在岛上繁殖然后成为domain species(说marshell这个岛的四个不同的子代蜥蜴起初的祖先应该就是两只带有两种不同基因的蜥蜴结合而来的四个daughter，这里有填句子)， 坏处就是这种繁殖会使得生物缺乏由于不同基因组合而带来的进化机会。因为无性繁殖子代和母代会share一样的。 所以这种无性繁殖适合在岛上因为少predator并且少competition。倒数第二段吧，说了human对于这个蜥蜴的影响，蜥蜴很容易就藏在canoe里被人不经意地通过贸易带去岛上。之后一两段讲了这个动物的某个specie的分布刚好跟什么人的航行路线相符，而且它们又很小，可能就是自己偷偷爬到船上跟着来的。

参考阅读

参考： Plant and Animal Life of the Pacific Islands

There are both great similarities and considerable diversity in the ecosystems that evolved on the islands of Oceania in and around the Pacific Ocean. The islands, such as New Zealand, that were originally parts of continents still carry some small plant and animal remnants of their earlier biota (animal and plant life), and they also have been extensively modified by evolution, adaptation, and the arrival of new species. By contrast, the other islands, which emerged via geological processes such as volcanism, possessedno terrestrial life, but over long periods, winds, ocean currents, and the feet, feathers, and digestive tracts of birds brought the seeds of plants and a few species of animals. Only those species with ways of spreading to these islands were able to undertake the long journeys, and the various factors at play resulted in diverse combinations of new colonists on the islands. One estimate is that the distribution of plants was 75 percent by birds, 23 percent by floating, and only 2 percent by wind.

Finally, a fourth major factor in species distribution, and indeed in the shaping of Pacific ecosystems, was wind. It takes little experience on Pacific islands to be aware that there are prevailing winds. To the north of the equator these are called north-easterlies, while to the south they are called south-easterlies. Further south, from about 30^。south, the winds are generally from the west. As a result on nearly every island of significant size there is an ecological difference between its windward and leeward (away from the wind) sides. Apart from the wind action itself on plants and soils, wind has a major effect on rain distribution. The Big Island of Hawaii offers a prime example, one can leave Kona on the leeward side in brilliant sunshine and drive across to the windward side where the city of Hilo is blanketed in mist and rain.

While such localized plant life and climatic conditions are very noticeable, over Oceania as a whole there is relatively little biodiversity, and the smaller the island and the further east it lies, the less there is likely to be. When humans moved beyond the islands of Near Oceania (Australia, New Guinea, and the Solomon Islands), they encountered no indigenous mammals except for flying foxes, fruit bats, and seals on some islands. Other vertebrate species were restricted to flying animals and a few small reptiles. However, local adaptations and evolution over long periods of isolation promoted fascinating species adaptations to local conditions. Perhaps most notable, in the absence of mammals and other predators, are the many species of flightless and ground-nesting birds. Another consequence of evolution was that many small environments boasted their own endemic (native) species, often small in number, unused to serious predation, limited in range, and therefore vulnerable to disruption. In Hawaii, for example, the highly adapted 39 species and subspecies of honeycreepers, several hundred species of fruit flies, and more than 750 species of tree snails are often cited to epitomize the extent of localized Oceanic endemism (species being native to the area).

Passage Ten

学科分类

题目

社科类

欧洲始祖语言

内容回忆

欧洲始祖语言的起源，比如少量军事精锐征服传播理论，大量人口西迁融合理论

参考阅读

7-3 Agriculture, Iron, and the Bantu Peoples

There is evidence of agriculture in Africa prior to 3000 B.C. It may have developed independently, but many scholars believe that the spread of agriculture and iron throughout Africa linked it to the major centers of the Near East and Mediterranean world. The drying up of what is now the Sahara desert had pushed many peoples to the south into sub-Sahara Africa. These peoples settled at first in scattered hunting-and-gathering bands, although in some places near lakes and rivers, people who fished, with a more secure food supply, lived in larger population concentrations. Agriculture seems to have reached these people from the Near East, since the first domesticated crops were millets and sorghums whose origins are not African but west Asian. Once the idea of planting diffused, Africans began to develop their own crops, such as certain varieties of rice, and they demonstrated a continued receptiveness to new imports. The proposed areas of the domestication of African crops lie in a band that extends from Ethiopia across southern Sudan to West Africa. Subsequently, other crops, such as bananas, were introduced from Southeast Asia.

Livestock also came from outside Africa. Cattle were introduced from Asia, as probably were domestic sheep and goats. Horses were apparently introduced by the Hyksos invaders of Egypt (1780-1560 B.C.) and then spread across the Sudan to West Africa. Rock paintings in the Sahara indicate that horses and chariots were used to traverse the desert and that by 300-200 B.C., there were trade routes across the Sahara. Horses were adopted by peoples of the West African savannah, and later their powerful cavalry forces allowed them to carve out large empires. Finally, the camel was introduced around the first century A.D. This was an important innovation, because the camel’s abilities to thrive in harsh desert conditions and to carry large loads cheaply made it an effective and efficient means of transportation. The camel transformed the desert from a barrier into a still difficult, but more accessible, route of trade and communication.

Iron came from West Asia, although its routes of diffusion were somewhat different than those of agriculture. Most of Africa presents a curious case in which societies moved directly from a technology of stone to iron without passing through the intermediate stage of copper or bronze metallurgy, although some early copper-working sites have been found in West Africa. Knowledge of iron making penetrated into the forest and savannahs of West Africa at roughly the same time that iron making was reaching Europe. Evidence of iron making has been found in Nigeria, Ghana, and Mali.

This technological shift cause profound changes in the complexity of African societies. Iron represented power. In West Africa the blacksmith who made tools and  weapons had an important place in society, often with special religious powers and functions. Iron hoes, which made the land more productive, and iron weapons, which made the warrior more powerful, had symbolic meaning in a number of West Africa societies. Those who knew the secrets of making iron gained ritual and sometimes political power.

Unlike in the Americas, where metallurgy was a very late and limited development, Africans had iron from a relatively early date, developing ingenious furnaces to produce the high heat needed for production and to control the amount of air that reached the carbon and iron ore necessary for making iron. Much of Africa moved right into the Iron Age, taking the basic technology and adapting it to local conditions and resources.

The diffusion of agriculture and later of iron was accompanied by a great movement of people who may have carried these innovations. These people probably originated in eastern Nigeria. Their migration may have been set in motion by an increase in population caused by a movement of peoples fleeing the desiccation, or drying up, of the Sahara. They spoke a language, proto-Bantu (“Bantu”means “the people”), which is the parent tongue of a language of a large number of Bantu languages still spoken throughout sub-Sahara Africa. Why and how these people spread out into central and southern Africa remains a mystery, but archaeologists believe that their iron weapons allowed them to conquer their hunting-gathering opponents, who still used stone implements. Still, the process is uncertain, and peaceful migration—or simply rapid demographic growth—may have also caused the Bantu explosion.

所考词汇

1. advocate = support

2. intriguing = fascinating

3. minute = tiny

4. consequent = resulting

5. mechanisms-means

6. ultimately-eventually

7. flexible-bendable

8. rekindled-renewed

综合点评

个别同学有碰到16年旧题，难度适中

Conversation 1

话题分类

投稿

内容回忆

一个同学找广播站管理员投稿

Conversation 2

话题分类

停车

内容回忆

校园有展览无处停车，只能走路上学或者做学校的shuttle

Conversation 3

话题分类

教授问答

内容回忆

一个学生找教授问问题，教授提醒学生要期末考试了，记得看教材和笔记

Lecture 1

话题分类

脑神经

内容回忆

Daydreaming以及掌管这一行为的脑部区域，做实验来研究

Lecture 2

话题分类

历史学

内容回忆

16世纪权力的变更以及它在人们眼中重要性的变化

Lecture 3

话题分类

生态学

内容回忆

Green roof 分为内部和外部绿植来降低energy爱护环境

Lecture 4

话题分类

生物学

内容回忆

珊瑚礁里的鱼有鲜艳的蓝色，可以用来沟通和爱护自己

Task 1

内容回忆

【*旧题重现：2018年10月13日线下原题】

You are the members of two clubs in your school, but you have to quit one because this semester you have a lot of schoolwork to do. Which one do you prefer to quit? And why?

1. hiking club

2. speech and debate club

参考答案

If I were too busy to participate in both the hiking and speech club, I would quit the hiking club.

Although hiking is fun to do with friends, I can do it on my own whenever I have time. By contrast, it is impossible to get feedback about a speech or participate in a debate by myself.

Plus, I want to focus on things that will help me get a good job. Speech and debate are important work skills, so I think it is better to practice those now and do hiking later when I have more time.

Because speech and debate are hard to do on my own but are important for getting a good job, I would keep attending that club.

Task 2

阅读

学校要求开放论文库historical department

听力

同意

原因1：毕业论文和平时写的论文不一样，学生有模板的话可以更好地帮助他们写

原因2：现在论文都是存放在库里，不用也是浪费

Task 3

阅读

一个belief-bias effect信仰偏见效应，惯性思维就算有证据反对也不相信。

听力

例子是教授问头疼药的效果，学生都觉得有用，教授给他们看了一个research说是这个药没用，但是学生反而说可能是research的sample取样有问题。

Task 4

话题

动物hair毛发爱护自身的作用：

听力

1. 直接攻击predator

2. 立起毛发，使体型变大

综合点评

这次托福考试写作部分整体难度适中，综合写作是新的考题，独立写作有出现过类似的题目。

其中，综合写作考查的是分析解决型，而不是听力反驳阅读的常规题型。

独立写作考察的是线上线下考过多次的原题，问的是从年长些的朋友处获得的建议要比同龄朋友的建议来的更为宝贵

综合写作

话题分类

分析解决类

考题回忆

总论点

美国Erie Canal建造时的困难和解决方法

阅读部分

分论点一：自然环境terrain and landscape 会使建造变得艰难

分论点二：人手不够 lack of workers

分论点三：花钱太多benefits 不足以cover high cost

听力部分

反对并给出了解决方法

分论点一：用动物帮忙和冬天开工，用devices来帮助dig和remove roots，冬天才在区域开工

分论点二：欧洲有移民immigration，他们可能需要这份工作

分论点三：这个运河省钱省力，之后运输货物会更方便

解题思路

阅读部分

　　1. 1. 自然环境 该地的landscape有很多阻碍，比如有很多forests,砍伐耗时耗力，有很多湿地wetlands，所以蚊子很多，会传播疟疾malaria

　　2. 2. 建筑运河需要很多人工，人手不够

　　    3. 3. 这一带人很少，带来的经济效益没有办法弥补建造的巨大花费

听力部分

　　1. 1. 那时已经有可以将树木连根拔起的工具，并用牲口当动力，效率还是挺高的。关于湿地中的蚊子问题，工人可以在冬季施工，这样就不会有传播疟疾malaria的问题

　　2. 2. 那时候刚好有大量的移民，而移民需要大量的工作来糊口，这恰好解决了人工问题

　　3. 3. 这里居住以及路过的人很少，是因为交通非常不方便，但是canal修好后会完全改善。以前陆路运输需要6周100美元，canal修好后水路运输只需6天10美元，所以无人问津的状态将改变

参考范文

范文:

Both the reading and the listening discuss about problems of Erie canal construction. The reading raises three problems, while the lecturer provides corresponding solutions.

First, as the reading suggests, there are obstacles in the landscape like lots of forests, which makes logging energy-consuming and time consuming. Wetlands with mosquitoes also make the project harder to implement because of malaria-spreading. However, the listening points out that by the time the construct will be carried out, there will be an effective tool to pulling out the trees from the roots, powered by the livestock. As to the issue of malaria, as long as the project is arranged in winter season, this problem will be easily resolved.

Second, the reading mentions that there will be lack of labors to build the canal. The listening, on the other hand, points out that there will be a great number of immigrants coming by the time of construct and they will need lots of jobs to make a living.

Third, the reading also illustrates that the population size of the place is small, therefore the economic benefits of the construction can hardly compensate for the costs the project ensues. The listening, on the contrary, contend that the reason of the smaller population size is the inconvenience of transportation. The cost of transportation will be reduced dramatically from $100 per week via roads to $10 per week via water, therefore the number of people will definitely grow.

独立写作

话题分类

教育类

考题回忆

Do you agree or disagree with the following statement? Getting advice from friends who are older than you is more valuable than getting advice from friends of your same age.

本场考题是老题重现，在2014/11/8的B卷和2016/4/9 都考过

解题思路

写作思路：

要点：属于交友类话题，从年长的朋友的角度展开比较容易，可以思考年长带来的优势，比如经验、心理等

观点：agree

1.从专业知识的角度

（1）年长的朋友经历过课程选择、遭遇困难、攻克挑战的整个过程，从而可以给到具体化的有针对性的建议。

（2）年长的朋友更加理解学生的特有困难，也不会评判你的脆弱或无知，找他们要建议，没有后顾之忧

2.从人际技巧的角度

（1）生活中需要寻找建议的场景不仅仅是学习，还有人际技巧方面年青人需要听取过来人的。年长些的朋友阅历与视野更丰富，更可以给出有效用的方案。

（2）年长的朋友更知道大的画面，知道在各种任务中哪一个重要，这种谋略性思考也是同龄人很难超越的

3.让步：诚然有人认为现在世界变化如此之快以致于3-5年就能产生所谓的代沟，但是，信息的激增并不会改变人生的基本需要，也不会降低基本原则或核心价值观的重要性，所以总的说来，年长朋友的忠告会更宝贵。

参考范文

范文：

Friendship has been cherished throughout the history of all cultures, and has become even more indispensable with the growingly fierce competition. After all, only by heeding more valuable advices from our friends, our competitive advantages will be maximized. Some people trust older friends for their wisdom while others prefer listening to the insights of their peers. From my perspective, it is definitely more valuable to consult with older friends.

Firstly, older friends are better equipped with expertise and certainly more resourceful in academic performance than those friends of your same age. With a more systematic and comprehensive education, older friends are more intelligent to help you tackle a great variety of obstacles confronted by you. Besides, people become more compassionate and empathetic if they have experienced similar dilemma or difficulties that you are struggling with, so you don’t have to confront the misunderstanding or even judgmental attitude from novice in the field.

What’s more, advice from older friends are more constructive when it comes to social and interpersonal skills. Sooner or later, we need to learn how to interact with professors, employers, partners of all kinds, it is hard to imagine that your peer group friends would be as insightful and visionary since they are definitely less experienced and sophisticated compared with older friends. Older friends are also more strategic in their thinking, thanks to prioritizing all kinds of tasks to fulfill objectives, which makes their suggestion unique and efficacious.

Admittedly, some people argue that in this era of information explosion, even 3-5 years of age gap would make it harder for people to empathize with each other thoroughly, let along seeking advice from much older friends However, the ubiquity of information does not and will not alter the paramount core values and principles. What defines us and shapes our characters are timeless charisma, ingenuity and wisdom. Consequently we will always be depending on eminent minds of our older friends to be a more inspired, motivated and joyful individual.

To conclude, older friends and their advice are big assets. By interacting and mimicking them, we would be able to incorporate more resources, experiences and inspirations and stay away from confusions, blunders and frustrations.

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