大学六级-1186及答案解析.doc

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1、大学六级-1186 及答案解析(总分：712.00，做题时间：90 分钟)一、Part Writing(总题数：1，分数：106.00)1. （分数：106.00）_二、Part Reading Compr(总题数：1，分数：70.00)Earth: Melting in the Heat?Glaciers are melting; the ice caps are disappearing into the oceans; sea levels may rise by many meters as a consequence. Indigenous (本土的) Arctic peoples

2、will find their food stocks gone, while fresh water supplies in Asia and south America will disappear as the glaciers which provide them melt away; penguins, polar bears and seals will find their habitats gone, their traditional lives unlivable.But how realistic is this picture? Is the worlds ice re

3、ally disappearing, or is it unscientific hot air?A European satellite named Cryosat was designed to provide definitive answers to some of these questions. A launcher fault destroyed the mission in October 2005, but the European Space Agency has approved a replacement. In the meantime, here is our gl

4、obal snapshot.The AntarcticHuge, pristine (质朴的), dramatic, unforgivingthe Antarctic is where the biggest of all global changes could begin.There is so much ice here that if it all melted, sea levels globally would rise hugelyperhaps as much as 80m. Say goodbye to London, New York, Sydney, Bangkok.in

5、 fact, the majority of the worlds major cities.But will it happen? Scientists divide the Antarctic into three zones: the east and west Antarctic ice sheets; and the Peninsula, the tongue of land which points up towards the southern tip of South America.“Everybody thinks that the Antarctic is shrinki

6、ng due to climate change, but the reality is much more complex,“ says David Vaughan, a principal investigator at the British Antarctic Survey in Cambridge, U.K. “Parts of it appear to be thickening as a result of snowfall increases, but the Peninsula is thinning at an alarming rate due to warming. T

7、he West Antarctic sheet is also thinning, and were not sure of the reason why.“On the UpTemperatures in the Peninsula appear to be increasing at around twice the global averageabout 2 over the last 50 years. Those figures are based on measurements made by instruments at scientific stations.Earlier t

8、his year, David Vaughans group published research showing that the vast majority of glaciers along the Peninsula87% of the 244 studiedare in retreat. The ice dumped into the ocean as the glaciers retreat should not make much difference to global sea levelsperhaps a few centimeters.More worrying, pot

9、entially, are the vast ice sheets covering the rest of Antarctica. Making temperature measurements for the continent as a whole is difficult; it is a vast placemore than 2,000 km acrossthere are few research stations, and temperatures vary naturally by 23 from year to year. But measurements indicate

10、 that in the west, melting is underway.“About one-third of the West Antarctic ice sheet is thinning,“ says Dr. Vaughan, “on average by about 10 cm per year, but in the worst places by 34m per year.“The rock on which the West Antarctic ice rests is below sea level, and British Antarctic Survey resear

11、chers believe the thinning could be due to the ice sheet melting on its underside.“It may be that the ocean is warming and thats causing the ice to melt, but there may be other masons as well; for example, theres lots of volcanism in that area and so that could change how much heat is delivered to t

12、he underside of the ice sheet.“Cryosat should help to pin down what is happening at the West Antarctic fringe. The radar altimeters on board its predecessors ERS1 and ERS2 have been unable to map the steep slopes at the coast, whereas Cryosats instrument should be able to cope.If the entire West Ant

13、arctic ice sheet did melt, sea levels globally would rise, by around 5m. But at the moment, there is no sign of that happening.One recent scientific paper attempted to calculate probabilities for how much West Antarctic melting would contribute to global sea-level rises during this century. The conc

14、lusions: a 30% probability of a 20 cm rise, and a 5% chance of a 1m rise.Eastern MassAnd what of the big monster, the much larger East Antarctic sheet? A recent study using altimeter data suggested it is getting thicker, by about 1.8 cm/yr; another, using the gravity satellite mission Grace indicate

15、s its mass remains stable. But could rising temperatures in time drain the ice away?“It is not going to happen on any realistic human timescale,“ says David Vaughan. “Its so cold that you could raise temperatures by 510 without having much of an impact; its on rock above sea level, so warming in the

16、 ocean cant affect it.“Largely insulated from global trends and so big as to generate its own climatic systems, most of Antarctica appears to be immune to the big melt for now, though answers to what is happening in the west are eagerly awaited.The ArcticAt the top of the world, the Arctic is a regi

17、on built on water. Around the North Pole is ocean, with ice floes crowding in each winter and thinning again in the summers.In September, we learned from scientists at the U.S. National Snow and lee Data Center that the extent of ocean covered by ice is getting smaller each year, the current rate of

18、 shrinkage they calculate at around 8% per decade. Their projection is that within about 60 years, there will be no summer ice at all on the Arctic Ocean.“Overall, the extent has been declining, with some oscillations (摆动), since the 1970s when satellites were able to map it,“ comments Peter Wadhams

19、, Professor of Ocean Physics at Cambridge University, U.K., and currently at the Laboratoire Oce anographique in Villefranche-sur-mer, France. “Theres been a slow decline, but now the thinning appears to be more rapid. In the last two decades, not only has the area shrunk but the ice has got thinner

20、 by about 40%; the prediction is that it will vanish altogether during summers in the second half of this century.“Military RecordsMeasurements of thickness come mainly from military submarines, which spent long periods under the Arctic ice during the Cold War.Peter Wadhams was one of the scientists

21、 who afterwards persuaded the authorities in Britain and the United States to declassify their data.But as a method of measurement, it is far from perfect; and satellites have given only limited help. The existing satellite fleet gives good measurements of ice extent, but is not so good at detecting

22、 thickness, partly because the orbits of satellites with radar altimeters do not cover every portion of the ocean.This data deficit has led to a rival theorythat the ice is not melting at all; it is simply piling up in another part of the ocean, perhaps along the north Canadian coast.Peter Wadhams b

23、elieves he has now disproved this idea. “We did an experiment where we installed a set of buoys (浮标) in that region which measure the thickness of the ice and transmit it back via satellite,“ he says. “The buoy sits on the ice, and as waves pass under it they make it rise and fall, just by a millime

24、ter or two; measuring this allows you to calculate the thickness of the ice.“The preliminary results, announced at a scientific meeting in April 2005, show that the extra ice is not them; it really has melted away.Wider ImpactTo people living in the region, the melting brings mixed news. Current lif

25、estyles and staple foods will almost certainly change, but the open ocean may permit new opportunities for trade and agriculture.A bigger question is what it means for the rest of the planet, Ice reflects the suns radiation; water absorbs it. More water and less icea lower albedo (反照率)mean that the

26、pace of warming could increase. In this scenario, the Earth would be losing one of its “natural checks and balances“ against warminganother positive feedback mechanism.The Arctic is intimately tied to the global climate system, and disruptions here have the potential to create worldwide changesalbei

27、t (虽然) over long timescales. Possibly the most powerful link is via the thermohaline (热盐的) circulation, the global conveyor taking warm water along ocean surfaces and returning colder water at depth.“One very sensitive place is the middle of the Greenland Sea,“ says Peter Wadhams. “That has been ice

28、-free in the summer, but usually in winter it would be covered by a lobe of ice growing out from the Greenland coast. As it formed, it rejected salt back into the water, making the water heavier and helping it to sink. Since 1997, the ice tongue has never formed. That will be having an impact on the

29、 thermohaline circulation.“Back in geological history, about 55 million years ago, the Arctic was a warm (possibly 20) shallow sea that would have been ice-free without the intervention of a human-enhanced greenhouse effect.Natural variations may be playing a role in the picture seen now; but, as wi

30、th other parts of the planet, it is the speed of change that alarms many researchers as much as the change itself.（分数：70.00）(1).Fresh water supplies in Asia and south America is disappearing as the glaciers melt away.（分数：7.00）填空项 1:_(2).If all the ice in the Antarctic melted, global sea levels would

31、 rise hugely.（分数：7.00）填空项 1:_(3).According to David Vaughan, the Antarctic is shrinking due to climate change.（分数：7.00）填空项 1:_(4).David Vaughans group found that most of the glaciers along the Peninsula were in retreat.（分数：7.00）填空项 1:_(5).Cryosat should help figure out what is happening at the West

32、Antarctic fringe because its radar altimeters should be able to _.（分数：7.00）填空项 1:_(6).Most of Antarctica appears to be immune to the big melt for now because its largely insulated from global trends and its so big as to generate _.（分数：7.00）填空项 1:_(7).According to scientists at the U.S. National Snow

33、 and Ice Data Center. within about 60 years, there will be _ on the Arctic Ocean.（分数：7.00）填空项 1:_(8).The existing satellites are not good at detecting the thickness of the ice partly because the orbits of satellites with _ do not cover every portion of the ocean.（分数：7.00）填空项 1:_(9).To people living

34、in the Arctic. the melting of some glaciers may permit new opportunities for _.（分数：7.00）填空项 1:_(10).The ice tongue growing out from the Greenland coast used to reject salt back into the water, making _ heavier and helping it to sink.（分数：7.00）填空项 1:_三、Part Listening Com(总题数：0，分数：0.00)四、Section A(总题数：

35、3，分数：105.00)Questions 11 to 18 are based on the conversation you have just heard.（分数：56.00）A.She broke the microphone.B.She was interrupted by a phone call during her presentation.C.She is planning to give her presentation as soon as the microphone is fixed.D.The microphone broke just as she began h

36、er presentation.A.One month.B.One month and a half.C.Two months.D.Two months and a half.A.She should live in the country.B.She should live near the spring.C.He prefers to live in the country.D.He agrees with the woman.A.It is the best city hes ever visited.B.It was worse than he had expected.C.It is

37、 difficult to get around in the city.D.The hotel service is terrible in the city.A.He will choose a new topic to write the essay.B.He will choose the novel written by Shakespeare as the topic.C.He refuses to accept the mans advice.D.He is on the wrong track.A.Paper plates are cheaper than dishes.B.D

38、ishes break more easily than paper plates.C.There is no need to wash any dishes now.D.The womans roommate will return soon.A.She has not applied for any university yet.B.She will begin university classes in a few weeks.C.She does not know yet if a university will accept her.D.She is too busy to cont

39、act the university right now.A.Reconsider his position later.B.Allow the student to miss class.C.Lower the students grade.D.Suggest that the student try to reschedule the operationQuestions 19 to 21 are based on the conversation you have just heard.（分数：21.00）A.Its a market.B.Its a recreation center.

40、C.Its an algebra school.D.Its the name of a part-time job.A.Six.B.Seven.C.Five.D.Six or seven.A.It doesnt move at all.B.It moves much faster than regular lines.C.Its next to the regular lines.D.Its her favorite.Questions 22 to 25 are based on the conversation you have just heard.（分数：28.00）A.Lower pr

41、ices.B.More choices.C.More competition.D.More companies.A.Other American states.B.Foreign countries.C.Regions outside the city where people liveD.Other cities in the state where people liveA.Its run by the government.B.it appeals to most people.C.It offers much choiceD.Its a monopoly.A.Shell pay per

42、 minuteB.Shell pay a monthly service fee.C.Shell pay a yearly service fee.D.She wont have to pay.五、Section B(总题数：3，分数：70.00)Passage OneQuestions 26 to 28 are based on the passage you have just heard.（分数：21.00）A.Because they are too small to understand the roles.B.Because they are absent-minded.C.Bec

43、ause they dont have much time for it.D.Because they are not interested in it.A.A camera.B.A film.C.A photo.D.A picture.A.Time.B.Memory.C.Habit.D.Textbook.Passage TwoQuestions 29 to 31 are based on the passage you have just heard.（分数：21.00）A.Botany is a very ancient learning,B.People in the Stone Age

44、 knew a lot about plants.C.People in the Stone Age knew little about plants.D.Pre-industrial societies have little insights about plants.A.People who live in Amazon tribes dont think plants are the basis of the food pyramid.B.People who live in Amazon tribes dont regard botany as a special branch of

45、 knowledge.C.People who live in Amazon tribes know all the properties of plants in the jungle.D.People who live in Amazon tribes give some special names to botany.A.Agriculture in the industrialized world.B.Cultivated crops.C.The association between roses and humans.D.The discoveries of certain gras

46、ses.Passage ThreeQuestions 32 to 35 are based on the passage you have just heard.（分数：28.00）A.Almost one million.B.About 600 thousand.C.Nearly 400 thousand.D.Approximately 200 thousand.A.Residential areaB.Shopping centersC.Parking lots.D.Shopping centers or parking lots near stadiums or gymnasiums.A.

47、They have to break into the car.B.Five percent of the cars are left unlocked.C.They sometimes find car keys in the ignition and simply get in.D.They knock out the driver and get the car away.A.Young people who want to ride a car for joy.B.Professionals who steal cars for other crimes.C.People who la

48、ck money to buy a ear.D.Both A and B.六、Section C(总题数：1，分数：77.00)There is something hard to (36) about cherries. The small red fruit is a popular (37) food around the world. In northern areas, cherry trees are just beginning to produce flowers.Cherries are thought to be native to western Asia. There are two major kinds of cherries (38) in the world: sour and sweet.Sour cherries are not eaten fresh because they contain little sugar, Instead, they are (39) to make (40) foods like jellies and pies and to make (41) drinks. The United States is a maj