1、雅思（阅读）历年真题试卷汇编 3及答案与解析 0 You should spend about 20 minutes on Questions 1-13 which are based on Reading Passage 1 below. LEARNING BY EXAMPLES A Learning Theory is rooted in the work of Ivan Pavlov, the famous scientist who discovered and documented the principles governing how animals(humans include
2、d)learn in the 1900s. Two basic kinds of learning or conditioning occur, one of which is famously known as the classical conditioning. Classical conditioning happens when an animal learns to associate a neutral stimulus(signal)with a stimulus that has intrinsic meaning based on how closely in time t
3、he two stimuli are presented. The classic example of classical conditioning is a dogs ability to associate the sound of a bell(something that originally has no meaning to the dog)with the presentation of food(something that has a lot of meaning for the dog)a few moments later. Dogs are able to learn
4、 the association between bell and food, and will salivate immediately after hearing the bell once this connection has been made. Years of learning research have led to the creation of a highly precise learning theory that can be used to understand and predict how and under what circumstances most an
5、y animal will learn, including human beings, and eventually help people figure out how to change their behaviors. B Role models are a popular notion for guiding child development, but in recent years very interesting research has been done on learning by example in other animals. If the subject of a
6、nimal learning is taught very much in terms of classical or operant conditioning, it places too much emphasis on how we allow animals to learn and not enough on how they are equipped to learn. To teach a course of mine I have been dipping profitably into a very interesting and accessible compilation
7、 of papers on social learning in mammals, including chimps and human children, edited by Heyes and Galef(1996). C The research reported in one paper started with a school field trip to Israel to a pine forest where many pine cones were discovered, stripped to the central core. So the investigation s
8、tarted with no weighty theoretical intent, but was directed at finding out what was eating the nutritious pine seeds and how they managed to get them out of the cones. The culprit proved to be the versatile and athletic black rat(Rattus rattus)and the technique was to bite each cone scale off at its
9、 base, in sequence from base to tip following the spiral growth pattern of the cone. D Urban black rats were found to lack the skill and were unable to learn it even if housed with experienced cone strippers. However, infants of urban mothers cross fostered to stripper mothers acquired the skill, wh
10、ereas infants of stripper mothers fostered by an urban mother could not. Clearly the skill had to be learned from the mother. Further elegant experiments showed that naive adults could develop the skill if they were provided with cones from which the first complete spiral of scales had been removed;
11、 rather like our new photocopier which you can work out how to use once someone has shown you how to switch it on. In the case of rats, the youngsters take cones away from the mother when she is still feeding on them, allowing them to acquire the complete stripping skill. E A good example of adaptiv
12、e bearing we might conclude, but lets see the economies. This was determined by measuring oxygen uptake of a rat stripping a cone in a metabolic chamber to calculate energetic cost and comparing it with the benefit of the pine seeds measured by calorimeter. The cost proved to be less than 10% of the
13、 energetic value of the cone. An acceptable profit margin. F A paper in 1996 Animal Behaviour by Bednekoff and Balda provides a different view of the adaptiveness of social learning. It concerns the seed caching behaviour of Clarks nutcracker(Nucifraga columbiana)and the Mexican jay(Aphelocoma ultra
14、marina). The former is a specialist, caching 30,000 or so seeds in scattered locations that it will recover over the months of winter; the Mexican jay will also cache food but is much less dependent upon this than the nutcracker. The two species also differ in their social structure, the nutcracker
15、being rather solitary while the jay forages in social groups. G The experiment is to discover not just whether a bird can remember where it hid a seed but also if it can remember where it saw another bird hide a seed. The design is slightly comical with a cacher bird wandering about a room with lots
16、 of holes in the floor hiding food in some of the holes, while watched by an observer bird perched in a cage. Two days later cachers and observers are tested for their discovery rate against an estimated random performance. In the role of cacher, not only nutcracker but also the less specialised jay
17、 performed above chance; more surprisingly, however, jay observers were as successful as jay cachers whereas nutcracker observers did no better than chance. It seems that, whereas the nutcracker is highly adapted at remembering where it hid its own seeds, the social living Mexican jay is more adept
18、at remembering, and so exploiting, the caches of others. Questions 1-4 Reading Passage 1 has seven paragraphs A-G. Which paragraph contains the following information? Write the correct letter A-G in boxes 1-4 on your answer sheet. 1 A comparison between rats learning and human learning 2 A reference
19、 to the earliest study in animal learning 3 The discovery of who stripped the pine cone 4 A description of a cost-effectiveness experiment 4 Do the following statements agree with the information given in Reading Passage 1? In boxes 5-8 on your answer sheet write TRUE if the statement agrees with th
20、e information FALSE if the statement contradicts the information NOT GIVEN if there is no information on this 5 The field trip to Israel was to investigate how black rats learn to strip pine cones. （ A）真 （ B）假 6 The pine cones were stripped from bottom to top by black rats. （ A）真 （ B）假 7 It can be l
21、earned from other relevant experiences to use a photocopier. （ A）真 （ B）假 8 Stripping the pine cones is an instinct of the black rats. （ A）真 （ B）假 8 Complete the summary below using words from the box. Write your answers in boxes 9-13 on your answer sheet. While the Nutcracker is more able to cache s
22、eeds, the Jay relies【 R1】 _on caching food and is thus less specialized in this ability, but more【 R2】 _. To study their behavior of caching and finding their caches, an experiment was designed and carried out to test these two birds for their ability to remember where they hid the seeds. In the exp
23、eriment, the cacher bird hid seeds in the ground while the other【 R3】 _. As a result, the Nutcracker and the Mexican Jay showed different performance in the role of【 R4】 _at finding the seeds the observing【 R5】 _didnt do as well as its counterpart. less more solitary social cacher observer remembere
24、d watched Jay Nutcracker 9 【 R1】 10 【 R2】 11 【 R3】 12 【 R4】 13 【 R5】 13 You should spend about 20 minutes on Questions 14-26 which are based on Reading Passage 2 below. A New Ice Age William Curry is a serious, sober climate scientist, not an art critic. But he has spent a lot of time perusing Emanu
25、el Gottlieb Leutzes famous painting “George Washington Crossing the Delaware,“ which depicts a boatload of colonial American soldiers making their way to attack English and Hessian troops the day after Christmas in 1776. “Most people think these other guys in the boat are rowing, but they are actual
26、ly pushing the ice away,“ says Curry, tapping his finger on a reproduction of the painting. Sure enough, the lead oarsman is bashing the frozen river with his boot. “I grew up in Philadelphia. The place in this painting is 30 minutes away by car. I can tell you, this kind of thing just doesnt happen
27、 anymore.“ But it may again soon. And ice-choked scenes, similar to those immortalized by the 16th-century Flemish painter Pieter Brueghel the Elder, may also return to Europe. His works, including the 1565 masterpiece “Hunters in the Snow,“ make the now-temperate European landscapes look more like
28、Lapland. Such frigid settings were commonplace during a period dating roughly from 1300 to 1850 because much of North America and Europe was in the throes of a little ice age. And now there is mounting evidence that the chill could return. A growing number of scientists believe conditions are ripe f
29、or another prolonged cooldown, or small ice age. While no one is predicting a brutal ice sheet like the one that covered the Northern Hemisphere with glaciers about 12,000 years ago, the next cooling trend could drop average temperatures 5 degrees Fahrenheit over much of the United States and 10 deg
30、rees in the Northeast, northern Europe, and northern Asia. “It could happen in 10 years,“ says Terrence Joyce, who chairs the Woods Hole Physical Oceanography Department. “Once it does, it can take hundreds of years to reverse.“ And he is alarmed that Americans have yet to take the threat seriously.
31、 A drop of 5 to 10 degrees entails much more than simply bumping up the thermostat and carrying on. Both economically and ecologically, such quick, persistent chilling could have devastating consequences. A 2002 report titled “Abrupt Climate Change: Inevitable Surprises,“ produced by the National Ac
32、ademy of Sciences, pegged the cost from agricultural losses alone at $100 billion to $250 billion while also predicting that damage to ecologies could be vast and incalculable. A grim sampler: disappearing forests, increased housing expenses, dwindling freshwater, lower crop yields, and accelerated
33、species extinctions. The reason for such huge effects is simple. A quick climate change wreaks far more disruption than a slow one. People, animals, plants, and the economies that depend on them are like rivers, says the report: “For example, high water in a river will pose few problems until the wa
34、ter runs over the bank, after which levees can be breached and massive flooding can occur. Many biological processes undergo shifts at particular thresholds of temperature and precipitation.“ Political changes since the last ice age could make survival far more difficult for the worlds poor. During
35、previous cooling periods, whole tribes simply picked up and moved south, but that option doesnt work in the modern, tense world of closed borders. “To the extent that abrupt climate change may cause rapid and extensive changes of fortune for those who live off the land, the inability to migrate may
36、remove one of the major safety nets for distressed people,“ says the report. But first things first. Isnt the earth actually warming? Indeed it is, says Joyce. In his cluttered office, full of soft light from the foggy Cape Cod morning, he explains how such warming could actually be the surprising c
37、ulprit of the next mini-ice age. The paradox is a result of the appearance over the past 30 years in the North Atlantic of huge rivers of freshwater the equivalent of a 10-foot-thick layer mixed into the salty sea. No one is certain where the fresh torrents are coming from, but a prime suspect is me
38、lting Arctic ice, caused by a buildup of carbon dioxide in the atmosphere that traps solar energy. The freshwater trend is major news in ocean-science circles. Bob Dickson, a British oceanographer who sounded an alarm at a February conference in Honolulu, has termed the drop in salinity and temperat
39、ure in the Labrador Sea a body of water between northeastern Canada and Greenland that adjoins the Atlantic “arguably the largest full-depth changes observed in the modem instrumental oceanographic record.“ The trend could cause a little ice age by subverting the northern penetration of Gulf Stream
40、waters. Normally, the Gulf Stream, laden with heat soaked up in the tropics, meanders up the east coasts of the United States and Canada. As it flows northward, the stream surrenders heat to the air. Because the prevailing North Atlantic winds blow eastward, a lot of the heat wafts to Europe. Thats
41、why many scientists believe winter temperatures on the Continent are as much as 36 degrees Fahrenheit warmer than those in North America at the same latitude. Frigid Boston, for example, lies at almost precisely the same latitude as balmy Rome. And some scientists say the heat also warms Americans a
42、nd Canadians. “Its a real mistake to think of this solely as a European phenomenon,“ says Joyce. Having given up its heat to the air, the now-cooler water becomes denser and sinks into the North Atlantic by a mile or more in a process oceanographers call thermohaline circulation. This massive column
43、 of cascading cold is the main engine powering a deepwater current called the Great Ocean Conveyor that snakes through all the worlds oceans. But as the North Atlantic fills with freshwater, it grows less dense, making the waters carried northward by the Gulf Stream less able to sink. The new mass o
44、f relatively fresh water sits on top of the ocean like a big thermal blanket, threatening the thermohaline circulation. That in turn could make the Gulf Stream slow or veer southward. At some point, the whole system could simply shut down, and do so quickly. “There is increasing evidence that we are
45、 getting closer to a transition point, from which we can jump to a new state.“ Questions 14-17 Choose the correct letter A, B, C orD. Write your answers in boxes 14-17 on your answer sheet. 14 The writer uses paintings in the first paragraph to illustrate （ A） possible future climate change. （ B） cl
46、imate change of the last two centuries. （ C） the river doesnt freeze in winter anymore. （ D） how George Washington led his troops across the river. 15 Which of the following do scientists believe to be possible? （ A） The temperature may drop over much of the Northern Hemisphere. （ B） It will be cold
47、er than 12,000 years ago. （ C） The entire Northern Hemisphere will be covered in ice. （ D） Europe will look more like Lapland. 16 Why is it difficult for the poor to survive the next ice age? （ A） People dont live in tribes anymore. （ B） Politics are changing too fast today. （ C） Abrupt climate chan
48、ge causes people to live off their land. （ D） Migration has become impossible because of closed borders. 17 Why is continental Europe much warmer than North America in winter? （ A） Wind blows most of the heat of tropical current to Europe. （ B） Europe and North America are at different latitudes. （
49、C） The Gulf Stream has stopped yielding heat to the air. （ D） The Gulf Stream moves north along the east coast of North America. 17 Look at the following statements(Questions 18-22)and the list of people in the box below. Match each statement with the correct person A-D. Write the appropriate letter A-D in boxes 18-22 on your answer sheet NB You many wse any letter more than once. List of People A William Curry B Terrence Joyce C Bob Dickson D National Academy of Science 18 Most Americans are not prepared for the next ice age. 19 The result of abru
