大学六级-1349及答案解析.doc

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1、大学六级-1349 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 w

2、ill find their food stocks gone, while flesh 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 rea

3、lly 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, hut the European Space Agency has approved a replacement, in the meantime, here is our glo

4、bal snapshot.The AntarcticHuge, pristine(质朴的), dramatic, unforgiving-the 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 hugely-perhaps 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 Peninsula-87% of the 244 studied-are in retreat. The ice dumped into the ocean as the glaciers retreat should not make much difference to global sea levels-perhaps a few centimeters.More worrying,

9、potentially, 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 place-more than 2,000 km across-there are few research stations, and temperatures vary naturally by 2-3 from year to year. But measurements in

10、dicate that in the west, melting is underway.“About one-third of the West Antarctic ice sheet is thinning,“ says Dr. Vaughan, “un 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

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

12、ed to the 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 W

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

14、he conclusions: 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 i

15、ndicates 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 5-10 without having much of an impact; its on rock above sea level, so warmi

16、ng in the 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 arc eagerly awaited.The ArcticAt the top of the world, the Arctic

17、is a region 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 Ice Data Center that the extent of ocean covered by ice is getting smaller each year, the curren

18、t rate of 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

19、 Wadhams, 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

20、thinner by about 400; 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 sci

21、entists 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 de

22、tecting 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 theory-that 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 W

23、adhams believes 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 us waves pass under it they make it rise and fall, just by a

24、millimeter 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 there; it really has melted away.Wider ImpactTo people living in the region, the melting brings mixed news. Cur

25、rent lifestyles 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, lee reflects the suns radiation; water absorbs it. More water and less ice-a lower albedo (反照率 )-mea

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

27、changes-albeit(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 h

28、as been ice-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 im

29、pact on the 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;

30、 but, as with 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 l

31、evels would 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 a

32、t the West 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 m generate _.（分数：7.00）填空项 1:_(7).According to scientists at the U.S. Nat

33、ional Snow and lee 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

34、 living 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、Sectio

35、n A(总题数：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

36、 began her presentationA.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 women.A.It is the best city hes ever visited.B.It was worse than he had expected.

37、C.It is 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 dis

38、hes.B.Dishes break more easily than paper plates.C.There is no need to wash any dishes now.D.The womens 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

39、 to contact 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 operation.Questions 19 to 21 are based on the conversation you have just heard.（分数：21.00）A.Its a market.B.Its a recreatio

40、n canter.C.Its an algebra school.D.Its the name of a part4ime 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.

41、Lower prices.B.More choices.C.More competition.D.More companies.A.Other American states.B.Foreign countries.C.Regions outside the city where people live.D.Other cities in the state where people live.A.Its nm by the government.B.It appeals to most people.C.It offers much choice.D.Its a monopoly.A.She

42、ll pay per minute.B.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 rules.B.Because they are absent-m

43、inded.C.Because 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 th

44、e Stone Age 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 specia

45、l branch of knowledge.C.People who live in Amazon tribes know all the properties of plains in the jungle.D.People who live in Amazon tribes give some special names to botany.A.Agriculture in the industrialized worldB.Cultivated crops.C.The association between roses and humans.D.The discoveries of ce

46、rtain grasses.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 area.B.Shopping centers.C.Parking lots.D.Shopping centers or parking lots near stadiums or

47、gymnasiumsA.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.P

48、eople who lack money to buy a car.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 S