综合点评

Passage

one

学科分类

题目

科技

The Importance of Mail Service in the Early United States

内容回忆

首段： America formation promotescirculation of news and information, both velocity and volume ，people trades with one another indistance.

　　第二段：The United States PostOffice makes news circulation easy and free. 随后介绍了 two decisions that help postalsystem to improve integrate nation: one is post office is granted to sell allthe newspapers at low price, another is Congress never turning down anypetition for new road or new post service.

　　第三段：提出虽然 post service 由 political purpose 决定，但是它也影响了business，举了 wheat 的例子。

　　第四段：transportationimprovements. new built roads 提高了 mail service 的 capacity and speed up service,too。随着交通的发展，越来越多的方式 can deliver mails：sailing ship, stagecoach,steamboat, canal boat and railroad.

参考阅读

In the early days of the United States, postal charges were paid by the recipients, and charges varied with the distance carried. In 1825, the United States Congress permitted local postmasters to give letters to mail carriers for home delivery, but these carriers received no government salary and their entire compensation depended on what they were paid by the recipients of individual letters.

In 1847 the United States Post Office Department adopted the idea of a postage stamp, which of course simplified the payment for postal service but caused grumbling by those who did not like to prepay. Besides, the stamp covered only delivery to the post office and did not include carrying it to a private address. In Philadelphia, for example, with a population 150,000, people still had to go to the post office to get their mail. The confusion and congestion of individual citizens looking for their letters was itself enough to discourage use of the mail. It is no wonder that, during the years of these cumbersome arrangements, private letter-carrying and express businesses developed. Although their activities were only semilegal, they thrived, and actually advertised that between Boston and Philadelphia they were a halfday speedier than the government mail. The government postal service lost volume to private competition and was not able to handle efficiently even the business it had.

Finally, in 1863, Congress provided that the mail carriers who delivered the mail from the post offices to private addresses should receive a government salary, and that there should be no extra charge for that delivery. But this delivery service at first confined to cities, and free home delivery became a mark of urbanism. As late as 1887, a town had to have 10,000 people to be eligible for free home delivery. In 1890, of the 75 million people in the United States, fewer than 200 million had mail delivered free to their doors. The rest, nearly threequarters of the population, still received no mail unless they went to their post office.

Passage

two

学科分类

题目

生物学

Diversity of Rainforest

内容回忆

热带雨林动物和植物都具有多样性，介绍各种动物和植物，还有生活环境

参考阅读

Although they cover less than 2 percent of Earth's surface, rainforests house an estimated 50 percent of all life on the planet's land masses.

No one knows exactly how many species live in the world's tropical rainforests — estimates range from 3 to 50 million species — rainforests are the undisputed champions of biodiversity among the world's ecosystems, containing far higher numbers of species on a per-area basis relative to sub-tropical, temperate, and boreal ecosystems. For example, whereas temperate forests are often dominated by a half dozen tree species or fewer that make up 90 percent of the trees in the forest, a tropical rainforest may have more than 480 tree species in a single hectare (2.5 acres). A single bush in the Amazon may have more species of ants than the entire British Isles. This diversity of rainforests is not a haphazard event, but is the result of a series of unique circumstances.

Biodiversity -- short for biological diversity -- is the the number and types of organisms in an habitat, ecosystem, region or environment. It can refer to genetic, species, or habitat variation at any scale.

The hot and humid climate plays an important role in rainforest variety. As a general rule,diversity and ecosystem productivity increase with the amount of solar energy available to the system. Sunlight is captured in the leaves of canopy plants via photosynthesis, converted into simple sugars, and transferred throughout the forest energy system as the leaves and fruit are eaten or decomposed by various organisms. The primary measure of ecosystem net primary production is the fixation of carbon by plants. Tropical rainforests have the highest mean net primary production of any terrestrial ecosystem, meaning an acre of rainforest stores more carbon than an acre of any other vegetation type. The humid climate adds another ingredient essential to rich diversity: water.

The stable tropical rainforest environment promotes diversity by allowing plants and animals to interact all year round without needing to develop protection against cold or frost. In addition, because the sun shines all year long providing plants with the energy to manufacture food via photosynthesis there is no seasonal food shortage in the ecosystem. The abundant food source for plants (sunlight) is passed up through the system to herbivores, which consume the plant leaves, seeds, and fruits, to carnivores which consume the herbivores. Over the course of millions of years, with abundant food, rainforest species have adapted to take full advantages of all the available niches.

Millions of years of battle between predator and prey have resulted in an extensive array of defenses, weapons, and specializations. Camouflage, mimicry, specialized breeding and feeding habits, symbiotic relationships with other species, and other complex adaptations have allowed species to out-compete rivals by making use of resources not available to generalists. Virtually no niche in the rainforest is unfilled and many different species can coexist in a relatively small area, without encroaching on their neighbors. The evolutionary process continues and species are pushed into narrower and narrower niches until they are unbelievably specialized to their particular way of life.

This evolutionary process ensures that no one well-adapted species (i.e. beetle) dominates the whole population of beetles because that one species cannot be possibly adapted to all the niches available in the forest. As a generalist, the species would be quickly out-competed by more specialized species. Generalists appear to thrive most under disturbed conditions, such as areas cleared for agriculture. Here these "weedy" species may be quite common. Furthermore, any species abundant in natural forest faces the threat that a predator would adapt to exploit its abundance. For example, the failure of rubber tree (Hevea brasiliensis) plantations in the Amazon is due to leaf blight. In the ordinary rainforest, rubber trees are widely dispersed so blight can never wipe out more than one individual tree at a time.

Tropical rainforests are markedly different from temperate forests. In temperate regions many plant and animal species have wide distributions, and a forest may consist of a half dozen or so tree species. In contrast, tropical species have evolved to fit narrow niches in a relatively constant environment, producing grandiose diversity. For example, more than 480 tree species have been identified in a single hectare of tropical rainforest.

Visitors to the rainforest are often disillusioned by what they see because they confuse the word "diversity" with "abundance." They visit the rainforest expecting to see ten jaguars, dozens of iguanas lying on the lodge patio, and large toucans waiting for them with breakfast. You will not encounter giant herds of wildebeest or zebra as on the African savanna. Nor will you find an eruption of flowers or even an abundance of colorful birds. Life in the rainforest is strikingly subtle.

Rainforests are diverse, in terms of numbers of species, but any one given species is not necessarily plentiful. Some rainforest species have populations that number in the millions, whereas others may consist of a handful of individuals. The biology of tropical rainforests is a biology of rare species. The reason for this occurrence is that the majority of rainforest species are scarce over the range of the forest and may be common in only a few small areas where they are particularly well adapted. A certain species may be quite common in one area but exceedingly rare only 500 yards away, where it is replaced by another similar, but distinct, species. There are a few common species found in scattered patches and a great number of rare species scattered throughout a forest. Some of these species are extremely rare and on the verge of extinction, especially where the forest has been disturbed. The reason for this pattern is that many species are highly specialized to fit a particular niche. Where that niche exists, that species may have a large population and constantly produce offspring that head off to colonize new areas. However, the colonizers almost always fail, because they cannot compete with the specialized species of other areas. Thus these colonizers are rare in the areas where they try to establish a foothold.

Passage Three

学科分类

题目

气候学

El Niño

内容回忆

北美大草原的气候较大，与厄尔尼诺和另一个气候现象有关

参考阅读

El Niño

The cold Humboldt Current of the Pacific Ocean flows toward the equator along the coasts of Ecuador and Peru in South America. When the current approaches the equator, the westward-flowing trade winds cause nutrient-rich cold water along the coast to rise from deeper depths to more shallow ones. This upwelling of water has economic repercussions. Fishing, especially for anchovies, is a major local industry.

Every year during the months of December and January, a weak, warm countercurrent replaces the normally cold coastal waters. Without the upwelling of nutrients from below to feed the fish, fishing comes to a standstill. Fishers in this region have known the phenomenon for hundreds of years. In fact, this is the time of year they traditionally set aside to tend to their equipment and await the return of cold water. The residents of the region have given this phenomenon the name of El Niño, which is Spanish for "the child," because it occurs at about the time of the celebration of birth of the Christ child.

While the warm-water countercurrent usually lasts for two months or less, there are occasions when the disruption to the normal flow lasts for many months. In these situations, water temperatures are raised not just along the coast, but for thousands of kilometers offshore. Over the last few decades, the term El Niño has come to be used to describe these exceptionally strong episodes and not the annual event. During the past 60 years, at least ten El Niños have been observed. Not only do El Niños affect the temperature of the equatorial Pacific, but the strongest of them impact global weather.

The processes that interact to produce an El Niño involve conditions all across the Pacific, not just in the waters off South America. Over 60 years ago, Sir Gilbert Walker, a British scientist, discovered a connection between surface pressure readings at weather stations on the eastern and western sides of the Pacific. He noted that a rise in atmospheric pressure in the eastern Pacific is usually accompanied by a fall in pressure in the western Pacific and vice versa. He called this seesaw pattern the Southern Oscillation. It was later realized that there is a close link between El Niño and the Southern Oscillation. In fact, the link between the two is so great that they are often referred to jointly as ENSO (El Niño-Southern Oscillation).

During a typical year, the eastern Pacific has a higher pressure than the western Pacific does. This east-to-west pressure gradient enhances the trade winds over the equatorial waters. This results in a warm surface current that moves east to west at the equator. The western Pacific develops a thick, warm layer of water while the eastern Pacific has the cold Humboldt Current enhanced by upwelling. However, in other years the Southern Oscillation, for unknown reasons, swings in the opposite direction, dramatically changing the usual conditions described above, with pressure increasing in the western Pacific and decreasing in the eastern Pacific. This change in the pressure gradient causes the trade winds to weaken or, in some cases, to reverse. This then causes the warm water in the western Pacific to flow eastward, increasing sea-surface temperatures in the central and eastern Pacific. The eastward shift signals the beginning of an El Niño.

Scientists try to document as many past El Niño events as possible by piecing together bits of historical evidence, such as sea-surface temperature records, daily observations of atmospheric pressure and rainfall, fisheries’ records from South America, and the writings of Spanish colonists dating back to the fifteenth century. From such historical evidence we know that El Niños have occurred as far back as records go.  It would seem that they are becoming more frequent.  Records indicate that during the sixteenth century, an El Niño occurred on average every six years.  Evidence gathered over the past few decades indicates that El Niños are now occurring on average a little over every two years.  Even more alarming is the fact that they appear to be getting stronger. The 1997-1998 El Niño brought copious and damaging rainfall to the southern United States, from California to Florida. Snowstorms in the northeast portion of the United States were more frequent and intense than in most years.

Passage Four

学科分类

题目

生物学

The  role of bird song

内容回忆

Bird song learning has become a powerful model system for studying learning because of its parallels with human speech learning, recent advances in understanding of its neurobiological basis, and the strong tradition of studying song learning in both the laboratory and the field. Most of the findings and concepts in the field derive from the tape-tutor experimental paradigm, in which the young bird is tutored by tape-recorded song delivered by a loudspeaker in an isolation chamber. This paradigm provides rigorous experimental control of auditory parameters, but strips song learning of any social context, and has slowed the realization that social factors might be critical to the process. In recent years, field research and lab studies using live birds as tutors have revealed that social factors play a preeminent role in song learning. In this article, we propose a new experimental paradigm-the virtual-tutor design, which permits precise manipulation of singing interactions between simulated tutors that the young bird "overhears," as well as direct singing interactions between the young bird and the simulated tutors. We suggest that this approach may permit researchers to analyze social factors in bird song learning, particularly those relating to auditory interactions, that have been difficult to analyze heretofore.

参考阅读

Many signals that animals make seem to impose on the signalers costs that are overly damaging. A classic example is noisy begging by nesting songbirds when a parent returns to the nest with food.  These loud cheeps and peeps might give the location of the nest away to a listening hawk or raccoon, resulting in the death of the defenseless nestlings.  In fact, when tapes of begging tree swallows were played at an artificial swallow nest containing an egg, the egg in that “noisy” nest was taken or destroyed by predators before the egg in a nearby quiet nest in 29 of 37 trials.  

    Further evidence for the costs of begging comes from a study of differences in the begging calls of warbler species that nest on the ground versus those that nest in the relative safety of trees. The young of ground-nesting warblers produce begging cheeps of higher frequencies than do their tree-nesting relatives. These higher-frequency sounds do not travel as far, and so may better conceal the individuals producing them, who are especially vulnerable to predators in their ground nests. David Haskell created artificial nests with clay eggs and placed them on the ground beside a tape recorder that played the begging calls of either tree-nesting or of ground-nesting warblers. The eggs “advertised” by the tree-nesters’ begging calls were found bitten significantly more often than the eggs associated with the ground-nesters’ calls.

    The hypothesis that begging calls have evolved properties that reduce their potential for attracting predators yields a prediction baby birds of species that experience high rates of nest predation should produce softer begging signals of higher frequency than nestlings of other species less often victimized by nest predators. This prediction was supported by data collected in one survey of 24 species from an Arizona forest, more evidence that predator pressure favors the evolution of begging calls that are hard to detect and pinpoint

    Given that predators can make it costly to beg for food, what benefit do begging nestlings derive from their communications? One possibility is that a noisy baby bird provides accurate signals of its real hunger and good health, making it worthwhile for the listening parent to give it food in a nest where several other offspring are usually available to be fed. If this hypothesis is true, then it follows that nestlings should adjust the intensity of their signals in relation to the signals produced by their nestmates, who are competing for parental attention. When experimentally deprived baby robins are placed in a nest with normally fed siblings, the hungry nestlings beg more loudly than usual – but so do their better-fed siblings, though not as loudly as the hungrier birds.

    If parent birds use begging intensity to direct food to healthy offspring capable of vigorous begging, then parents should make food delivery decisions on the basis of their offspring’s calls. Indeed, if you take baby tree swallows out of a nest for an hour, feeding half the set and starving the other half, when the birds are replaced in the nest, the starved youngsters beg more loudly than the fed birds, and the parent birds feed the active beggars more than those who beg less vigorously.

    As these experiments show, begging apparently provides a signal of need that parents use to make judgments about which offspring can benefit most from a feeding. But the question arises, why don’t nestlings beg loudly when they aren’t all that hungry? By doing so, they could possibly secure more food, which should result in more rapid growth or larger size, either of which is advantageous. The answer lies apparently not in the increased energy costs of exaggerated begging – such energy costs are small relative to the potential gain in calories – but rather in the damage that any successful cheater would do to its siblings, which share genes with one another. An individual’s success in propagating his or her genes can be affected by more than just his or her own personal reproductive success. Because close relatives have many of the same genes, animals that harm their close relatives may in effect by destroying some of their own genes. Therefore, a begging nestling that secures food at the expense of its siblings might actually leave behind fewer copies of its genes overall than it might otherwise.

Passage

Five

学科分类

题目

工业

Difference between factories and artisans

内容回忆

讲述工业革命时期，手工业作坊，工厂等和手艺人之间的区别与划分

参考阅读

Artisans in Sixteenth-Century Europe

For centuries European artisans had operated in small, autonomous handicraft businesses, but by the sixteenth century an evolving economic system—moving toward modern capitalism, with its free-market pricing, new organization of production, investments, and so on—had started to erode their stable and relatively prosperous position. What forces contributed to the decline of the artisan?

In a few industries there appeared technological innovations that cost more to install and operate than artisans—even associations of artisans—could afford. For example, in iron production, such specialized equipment as blast furnaces, tilt hammers, wire-drawing machines, and stamping, rolling, and slitting mills became more familiar components of the industry. Thus the need for fixed capital (equipment and buildings used in production) soared. Besides these items, expensive in their own right, facilities for water, storage, and deliveries were needed. In addition, pig (raw) iron turned out by blast furnaces could not be forged until refined further in a new intermediate stage. In late sixteenth-century Antwerp, where a skilled worker earned 125 to 250 guilders a year, a large blast furnace alone cost 3,000 guilders, and other industrial equipment was equally or more expensive.

Raw materials, not equipment, constituted artisans’ major expense in most trades, however. Whereas in 1583 an Antwerp silk weaver paid 12 guilders for a loom( and made small payments over many years to pay off the debt for purchasing the loom), every six weeks he or she had to lay out 24 guilders for the 2 pounds of raw silk required to make a piece of cloth. Thus access to cheap and plentiful primary materials was a constant preoccupation for independent producers. Using local materials might allow even the poorest among them to avoid reliance on merchant suppliers. The loss of nearby sources could therefore be devastating. As silk cultivation waned around the Spanish cities of Cordoba and Toledo, weavers in these cities were forced to become employees of merchants who put out raw silk from Valencia and Murcia provinces. In the Dutch Republic, merchants who imported unprocessed salt from France, Portugal, and Spain gained control of the salt-refining industry once exploitation of local salt marshes was halted for fear that dikes (which held back the sea from the low-lying Dutch land) would be undermined.

Credit was necessary for production but created additional vulnerabilities for artisans. Prices for industrial products lagged behind those of raw materials and foodstuffs, and this, coupled with rising taxes, made it difficult for many producers to repay their creditors. Periodic downturns, when food prices shot up and demand for manufactures fell off, drove them further into debt or even into bankruptcy, from which they might emerge only by agreeing to sell their products exclusively to merchants or fellow artisans who extended them loans. Frequent enough during periods of growth, such credit crises became deeper and lasted longer after about 1570, as did war-related disruptions of raw-material supplies and markets.

Artisans’ autonomy was imperiled, too, by restrictions on their access to markets. During the sixteenth century, a situation like this often resulted from the concentration of export trade in a few great storage and distribution centers. The disappearance of regional markets where weavers in Flanders (what is now northern Belgium) had previously bought flax and sold linen left them at the mercy of big-city middlemen, who quickly turned them into domestic workers. In a similar fashion, formerly independent producers in southern Wiltshire in England, who had bought yarn from spinners or local brokers and sold their cloth to merchants in nearby Salisbury, because subject to London merchants who monopolized both wool supplies and woolens exports.

With good reason, finally, urban artisans feared the growth of industries in the countryside. For one thing, they worried that the spread of village crafts would reduce their supply of raw materials, driving up prices. City producers also knew that rural locations enjoyed lower living costs, wages, and taxes, and often employed fewer or simplified processes. These advantages became a major preoccupation as competition intensified in the 1570s and 1580s.

Passage

Six

学科分类

题目

文化艺术

Film editing technology

内容回忆

电影剪辑技术的发展过程

参考阅读

Most people think of film editing as a technical job. However there is a reason the editing award is grouped with the other creative awards during the Oscar ceremony - because film editing is an art, not a science. If you've ever wondered what it is that film editors do, this article can open your mind to a world of creativity and artistry.

Film editing is one of the primary creative roles in film making, however, the editor's job does not begin until the film has already been shot. Once the director has finished filming the last scene in the documentary or action film, all of the footage is handed over to the editor and the editing magic begins. Editors have a big job which requires them to archive, watch, and select scenes from hundreds of hours of footage, so they generally have staff which includes assistants to help them with the grunt work.

It is the editor's job to view the many different scenes the director has shot - including each separate take, which can be captured on three or more cameras placed at different vantage points, and choose the shots and angles which best tell the story of the movie. It is the editor who decided when to cut away from a conversation to show what the characters are arguing over, when to show both characters, when to show only one, and how everything should all be fit together.

For a sequence such as a montage, often the disparate elements of the montage will be shot separately and it is the editor's job to decide which elements should be incorporated and when to best represent the product in a commercial or a theme in a movie. Editors will also generally have to work with the director, who will have notes and feedback on the editor's choices and may ask the editor to change some of what he or she has done.

In the early days of film editing, editors would have to cut and splice film negatives together seamlessly to make the final product. Though some editors still work this way, it is more likely that they will work on computers. For film-shot movies, this means scanning all the negatives into a computer. For digital films it is a much easier process of downloading all the footage to a powerful computer.

                          综合点评

今天的考试听力回忆内容比较残缺。

                         Conversation

话题分类

暂缺

内容回忆

暂缺

                               Lecture

话题分类

生物学

内容回忆

动物定位。

                               Lecture

话题分类

生物学

内容回忆

次声波信鸽 homing pigeon。

参考文章：机经35 L1

Task 1

内容回忆

家长该不该让学生用电子设备

参考答案

As far as I am concerned, I totally agree with the idea that electronic devices should not be allowed for students to use. Advertisements on TV are shown how portable they are and it is much more conducive to scholarly reading in our daily life. Apparently, what they want to do is to attract potential clientele and make further profits as soon as possible. Most of students can be encouraged to make purchase on electronic devices. But students who made purchase won’t be aware of something is gonna happen in the near future. Their study will be adversely affected by electronic devices and they’ll get used to relaxation. Time is in finitude.

Task 2

阅读

学生建议学校在假期开放部分教室，好处是能给学生带来好处，好处待补充

听力

女生反对

1. 假期有兴趣班，学校无法开放给其他人

2. 待补充

Task 3

阅读

化学手段捕捉猎物

听力

starfish为例子，视力不好，靠嗅觉捕捉浮游生物，浮游生物靠吃草维生

Task 4

话题

商业类：发展新项目产品

听力

公司打造产品，让别的公司先做，这样可以省钱，省时间，新产品会有用户投诉等。

综合点评

本次考试的综合题目和独立题目，难度适中，综合写作虽然不是以往重复过的题目，但是有过类似话题，独立任务更是常见原题，所以大家去刷以往的考题，多拓展思路，精准审题，丰富展开例证，祝取得好的成绩。

综合写作

话题分类

生态

考题回忆

总论点

为缓解全球变暖，向空中释放二氧化硫的火箭有三个问题

阅读部分

1. 产生酸雨，破坏环境

2. 价格很高，不划算

3. 效果不明显

听力部分

1. 酸雨也没有这么容易形成，需要特定条件，水汽少的时候不容易形成酸雨

2. 还有其他的办法，但是其实更昂贵

3. 有用的，即使温度变化很小，对缓解冰川融化有用。

解题思路

阅读部分仔细看，很多时候能够给我们一些听力内容方面的提示。

听力的细节一定尽可能的给全。

参考范文

Both reading and listening talks about how global warming has been deteriorating. According to the reading, there are three problems with the rocket that releasing sulfur dioxcide into the air, yet the professor in the listening casts doubt on the statement in the reading.

First, the reading points out the fact that it may produce acid rain, which affects the environment negatively. Yet the listening part explains that in fact acid rain is not that easy to produce; instead it only rains under specific condition. Specifically, there won't be acid rains when vapor is little. In this case, it's almost impossible to produce acid rain every time.

Second, the passage presents that the rocket costs a lot, which is not worthy at all. However, the listening makes it clear that indeed other ways are available, yet they are more expensive. So the price is quite fair to launch the rocket.

At last, the effect brought from rockets is little. But the professor mentions that it is effective actually. Even though the temperature hasn’t changed too much, it can alleviate glaciers melting. ［181］

独立写作

话题分类

健康

考题回忆

Nowadays it is easier to maintain good health than it was in the past.

解题思路

2017.8 , 2018.9, 2019.9 几乎每年都会考到此题或者类似的题目。对比类的题目一定注意在今昔上的比较。

参考范文

Since the past few years, lifestyles and patterns of people has refreshed in accordance with our surroundings. In modern society we are able to gain far more benefits compared to people living in the past though, but in my view, people today are harder to maintain a desired healthy physical condition.

For starters, due to a fast growing world, people, on average, are busier now than ever before, thus relying more on food delivery or instant foods to save time on cooking. A great many people who work in shift barely have time to cook meals by themselves, and have to eat take-outs or make instant noodles, even skip meals sometiems. Yet, either have fast food or foods from restaurants leads to serious health problems such as obesity, or worse, diabetes. On the contrary, making meals from raw materials bought from the market ensures healthier eating style, which is the way people commonly took in past 10 years. Now, the trend of having our meals outside has surely a higher risk of developing some potentional physical problems or certain illness. Therefore it is harder for people nowadays to stay healthy.

Also, with advanced technology, many daily chores and services used to be done by human are now replaced by electronic devices or robots, which indicates people are less physically active than before. For example, in those years when computers have not been popularized, people had to do many other things without computers, such as writing letters for communication. But nowadays, no matter teenagers or adults can’t live without their laptops and phones. Whether it is about playing video games, watching films, or studying and working, people can’t help depending healvily on their electronics, sitting in front of them all day, which hurts their backs and spines badly. This phenomenon then proves how technology development has resulted in a more sedentary life, and killed chances of people getting up and doing exercises.

It’s understandable that many people may bring out that currently there are better healthcare, advanced developments in medications, etc. than before, which helps to improve the health condition to some extent. Admittdedly, so far, many desirable resources are available for the public, but in fact, the truth is the factors that can affect our health greatly is not what can fix it, but what maintains it, which comes from our daily habits, such as on eating, sleeping, and exercising.

The fact that nowadays people have been increasingly relying on instant foods, delivery foods, and live a relatively sedentary life makes people unlikely to maintain as healthy as before.

［429］