1、考研英语（阅读）模拟试卷 130 及答案与解析Part B (10 points) 0 Researchers have found that drugs used to treat human seizures can delay aging in worms by as much as 50 percent. The roundworms used for the study are similar to humans in their molecular makeup, raising the possibility that the drugs could also extend th
2、e life span of humans.【R1】 _“By finding a class of drugs that delays aging we have found a relationship between the function of the nervous system and aging that was not well understood,“ said Kerry Kornfeld, a geneticist at the Washington University School of Medicine in St. Louis, Missouri. The fi
3、ndings are detailed this week in the journal Science.The discovery came out of the thesis work by one of Kornfelds graduate students, Kimberley Evason. About four years ago, Evason began exposing groups of the roundworm Caenorhabditis elegans to commercially available drugs to see if the drugs would
4、 delay aging or promote longevity.【R2】 _Over eight months the scientists tested 20 drugs, all with negative results. Finally they tested the anticonvulsant drug ethosuzimide. Researchers found that the drug extended the life span of roundworms from 16.7 days to 19.6 days, a 17 percent increase. 【R3】
5、 _The discovery that the drugs extend the life span of roundworms could have important implications for human aging as well. There are strong similarities on the molecular level between the proteins and genes that constitute the worm and those that make up other animals, including humans.“Many basic
6、 processes are highly related, including neural function, insulin signaling, and probably important aspects of the aging process,“ Kornfeld said. “Theres every reason to think that these animals are a good model for higher animals, such as people.“【R4】 _Ethosuzimide, which was developed in the 1950s
7、, is commonly used to treat epilepsy, though it is not known precisely how the drug controls convulsions. There is no anecdotal evidence that it has had an anti-aging effect in people. The next step, Kornfeld says, is to test if the drugs have an anti-aging effect on animals like flies and mice.Very
8、 little is known about the aging process. From genetic analysis, researchers have found that an insulin-like signaling system regulates aging and longevity. A good diet can delay aging and extend a persons life span. But scientists know virtually nothing about the effect of drugs on aging. “Its a bi
9、g void,“ Kornfeld said.In addition to delaying age-related degenerative changes, the drugs also increased neuromuscular activity, suggesting a link between the neuromuscular system and the aging process.【R5】 _There may also be other targets not yet explored that affect aging and neuromuscular functi
10、on. Said Kornfeld: “The process of aging remains mysterious.“Word count: 438A. But Kornfeld said scientists will not know about the applicability of the drugs in humans until a similar study is done on humans. “Whats very encouraging is that these drugs were developed to treat humans, and they are w
11、ell understood, because theyve been used for a long time,“ he said.B. Later the scientists discovered that two related anticonvulsant drugs also lengthened the lives of the wormsin the case of one drug, by almost 50 percent. “This was a big surprise to us, Kornfeld said. “We didnt think anticonvulsa
12、nt drugs had any particular relationship to aging. That connection was completely unexpected.“C. Roundworms are a poor subject for experiments, because they are not like humans, even though their molecules are similar. For example, they have no bones, nor do they show emotions, making it difficult t
13、o know how exactly human subjects would react to these drugs in large quantities. However, using the worms allows experiments to be conducted quickly, because they do not live for long.D. “Somehow the neural activity seems to regulate the aging of all of the bodythe skin, musculature, and reproducti
14、ve tract,“ Kornfeld said. “Somehow the nervous system coordinates the progress of all these tissues, evidently, though the life stages. But we dont know how it does that.“E. The discovery may also shed light on the little-understood aging process. Since the drugs act on the neuromuscular systems of
15、both humans and worms, the findings hint at a link between neural activity and aging.F. Unlike vertebrates, the worms are ideal subjects for the study of aging because of their short life spans, which last only a couple of weeks in a laboratory. The worm is well known in genetics, and the worms geno
16、me has been sequenced.G. Use of this drug has been permitted by law since 1998 and wider use is now expected as a result of the studies. “We can clearly link this drug with human aging, but we still need to find proof,“ says Kornfeld optimistically.1 【R1 】2 【R2 】3 【R3 】4 【R4 】5 【R5 】5 Climate change
17、 is with us. A decade ago, it was conjecture. Now the future is unfolding before our eyes. Canadas Inuit see it in disappearing Arctic ice and permafrost. The shantytown dwellers of Latin America and Southern Asia see it in lethal storms and floods. Europeans see it in disappearing glaciers, forest
18、fires and fatal heat waves. Scientists see it in tree rings, ancient coral and bubbles trapped in ice cores. These reveal that the world has not been as warm as it is now for a millennium or more. The three warmest years on record have all occurred since 1998; 19 of the warmest 20 since 1980. And Ea
19、rth has probably never warmed as fast as in the past 30 yearsa period when natural influences on global temperatures, such as solar cycles and volcanoes should have cooled us down. 【R1】_ People are causing the change by burning natures vast stores of coal, oil and natural gas. This releases billions
20、 of tonnes of carbon dioxide(CO2)every year, although the changes may actually have started with the dawn of agriculture, say some scientists. The physics of the “greenhouse effect has been a matter of scientific fact for a century. CO2 is a greenhouse gas that traps the Suns radiation within the tr
21、oposphere, the lower atmosphere. It has accumulated along with other man-made greenhouse gases, such as methane and chlorofluorocarbons(CFCs). Some studies suggest that cosmic rays may also be involved in warming. If current trends continue, we will raise atmospheric CO2 concentrations to double pre
22、-industrial levels during this century. That will probably be enough to raise global temperatures by around 2C to 5C. Some warming is certain, but the degree will be determined by cycles involving melting ice, the oceans, water vapor, clouds and changes to vegetation. 【R2】_ As natural ecosystems-suc
23、h as coral reefs-are disrupted, biodiversity is reduced. Most species cannot migrate fast enough to keep up, though others are already evolving in response to warming. 【R3 】_ The global warming would be more pronounced if it were not for sulphur particles and other pollutants that shade us, and beca
24、use forests and oceans absorb around half of the CO2 we produce. But the accumulation rate of atmospheric CO2 has doubled since 2001, suggesting that natures ability to absorb the gas could now be stretched to the limit. Recent research suggests that natural CO2 “sinks“, like peat bogs and forests,
25、are actually starting to release CO2. At the Earth Summit in 1992, the world agreed to prevent “dangerous“ climate change. The first step was the 1997 Kyoto Protocol, which will now finally come into force during 2005. It will bring modest emission reductions from industrialised countries. But many
26、observers say deeper cuts are needed and developing nations, which have large and growing populations, will one day have to join in. 【R4】_ In any case, according to the IPCC, the world needs to quickly improve the efficiency of its energy usage and develop renewable non-carbon fuels like: wind, sola
27、r, tidal, wave and perhaps nuclear power. It also means developing new methods of converting this clean energy into motive power, like hydrogen fuel cells for cars. 【R5】_ The bottom line is that we will need to cut CO2 emissions by 70% to 80% simply to stabilise atmospheric CO2 concentrationsand thu
28、s temperatures. The quicker we do that, the less unbearably hot our future world will be. Word count: 568 A. Climatologists reporting for the UN Intergovernmental Panel on Climate Change(IPCC)say we are seeing global warming caused by human activities. B. Other less conventional solutions include id
29、eas to stave off warming by “bega-engineering“ the planet with giant mirrors to deflect the Suns rays, seeding the oceans with iron to generate algal blooms, or burying greenhouse gases below the sea. C. Others claim that global warming is impossible to prevent and that the Kyoto Protocol came too l
30、ate. Besides, creating new forms of energy would cost too much money and no country has the resources required. D. Scientists have calculated the temperatures experienced at different locations in the Arctic and Antarctic by checking ice samples. These ice samples invariably contain minute particles
31、 of dust, grain, or pollen, which can be identified and their molecular make-up examined in order to ascertain the precise conditions under which they were produced. E. Some, including the US Bush administration, say the scientific uncertainty over the pace of climate change is grounds for delaying
32、action. The US and Australia have reneged on Kyoto. But most scientists believe we are under-estimating the dangers. F. Thermal expansion of the oceans, combined with melting ice on land, is also raising sea levels. In this century, human activity could trigger an irreversible melting of the Greenla
33、nd ice sheet. This would condemn the world to a rise in sea level of six metresenough to flood land occupied by billions of people. G. Warming is bringing other unpredictable changes. Melting glaciers and precipitation are causing some rivers to overflow, while evaporation is emptying others. Diseas
34、es are spreading. Some crops grow faster while others see yields slashed by disease and drought. Clashes over dwindling water resources may cause conflicts in many regions.6 【R1 】7 【R2 】8 【R3 】9 【R4 】10 【R5 】10 On Sept. 29, the House of Representatives passed a bill with overwhelming support from bo
35、th Democrats and Republicans. It would punish China for keeping its currency undervalued by slapping tariffs on Chinese goods. Everyone seems to agree that its about time. But it isnt. The bill is at best pointless posturing and at worst dangerous demagoguery. 【R1 】_Theres no doubt that China keeps
36、the renminbi, its currency, undervalued so it can help its manufacturers sell their toys, sweaters and electronics cheaply in foreign markets, especially the U.S. and Europe. But this is only one of a series of factors that have made China the key manufacturing base of the world. 【R2】_Chinese compan
37、ies make many goods for less than 25% of what they would cost to manufacture in the U.S. Making those goods 20% more expensive(because its reasonable to suppose that without government intervention, Chinas currency would increase in value against the dollar by about 20%)wont make American factories
38、competitive. The most likely outcome is that it would help other low-wage economies like Vietnam, India and Bangladesh, which make many of the same goods as China.【R3】 _Weve seen this movie before. From July 2005 to July 2008, under pressure from the U.S. government, Beijing allowed its currency to
39、rise against the dollar by 21%. Despite that hefty increase, Chinas exports to the U.S. continued to grow mightily.Look elsewhere in the past and you come to the same conclusion. In 1985 the U.S. browbeat Japan at the Plaza Accord meetings into letting the yen rise. But the subsequent 50% increase d
40、id little to make American goods more competitive. Yale Universitys Stephen Roach points out that since 2002, the U.S. dollar has fallen in value by 23% against all our trading partners, and yet American exports are not booming. 【R4】 _The real challenge we face from China is not that it will keep fl
41、ooding us with cheap goods. Its actually the opposite: China is moving up the value chain, and this could constitute the most significant new competition to the U.S. economy in the future.Now China wants to get into higher-quality goods and services. That means the next phase of its economic develop
42、ment, clearly identified by government officials, requires it to invest in human capital with the same determination it used to build highways. Since 1998, Beijing has undertaken a massive expansion of education, nearly tripling the share of GDP devoted to it. In the decade since, the number of coll
43、eges in China has doubled and the number of students quintupled, going from 1 million in 1997 to 5.5 million in 2007. China has identified its nine top universities and singled them out as its version of the Ivy League. At a time when universities in Europe and state universities in the U.S. are cru
44、mbling from the impact of massive budget cuts, China is moving in exactly the opposite direction.【R5】 _Word count: 485A. For much of the past three decades, China focused its efforts on building up its physical infrastructure. It didnt need to invest in its people; the country was aiming to produce
45、mainly low-wage, low-margin goods.B. China has built the largest higher-education sector in the world in merely a decades time. In fact, the increase in Chinas postsecondary enrollment since the turn of the millennium exceeds the total postsecondary enrollment in the United States.C. It wont solve t
46、he problem it seeks to fix. More worrying, it is part of growing anti-Chinese sentiment in the U.S. that misses the real challenge of Chinas next phase of development.D. Of course, once the recession hit, Chinas exports slowed, but not as much as those of countries that had not let their currencies
47、rise. So even with relatively pricier goods, China did better than other exporting nations.E. The U.S. imports more than it exports from 90 countries around the world. Is this because of currency manipulation by those countries, or is it more likely a result of fundamental choices we have made as a
48、country to favor consumption over investment and manufacturing?F. The others include low wages, superb infrastructure, hospitality to business, compliant unions and a hard-working labor force. A simple appreciation of the renminbi will not magically change all this.G. So Walmart would still stock go
49、ods at the lowest possible price, only more of them would come from Vietnam and Bangladesh. Moreover, these other countries, and many more in Asia, keep their currencies undervalued as well. As Helmut Reisen, head of research for the Development Center at the Organisation for Economic Co-operation and Development, wrote recently in an essay, “There are more than two currencies in the world.“11 【R1 】12 【R2 】13 【R3 】14 【R4 】15 【R5 】15 The mere sight of a snake or spider strikes t
