【考研类试卷】考研英语-试卷271及答案解析.doc
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1、考研英语-试卷 271及答案解析(总分:142.00,做题时间:90 分钟)一、Use of English(总题数:2,分数:80.00)1.Section I Use of EnglishDirections: Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D.(分数:40.00)_Most plants can make their own food from sunlight, (1)_ some have discovered that stea
2、ling is an easier way to live, Thousands of plant species get by (2)_ photosynthesizing, and over 400 of these species seem to live by pilfering sugars from an underground (3)_ of fungi(真菌). But in (4)_ a handful of these plants has this modus operandi been traced to a relatively obscure fungus. To
3、find out how (5)_ are (6)_, mycologist Martin Bidartondo of the University of California at Berkeley and his team looked in their roots. What they found were (7)_ of a common type of fungus, so (8)_ that it is found in nearly 70 percent of all plants. The presence of this common fungus in these plan
4、ts not only (9)_ at how they survive, says Bidartondo, but also suggests that many ordinary plants might prosper from a little looting, too. Plants have (10)_ relations to get what they need to survive. Normal, (11)_ plants can make their own carbohydrates through photosynthesis, but they still need
5、 minerals. Most plants have (12)_ a symbiotic relationship with a (13)_ network of what are called mycorrhizal fungi, which lies beneath the forest (14)_. The fungi help green plants absorb minerals through their roots, and (15)_, the plants normally (16)_ the fungi with sugars, or carbon. With a nu
6、mber of plants sharing the same fungal web, it was perhaps (17)_ that a few cheatersdubbed epiparasiteswould evolve to beat the system. (18)_, these plants reversed the flow of carbon, (19)_ it into their roots from the fungi (20)_ releasing it as “payment“.(分数:40.00)A.butB.ifC.becauseD.thoughA.forB
7、.withC.toD.withoutA.realmB.netC.relationD.webA.onlyB.almostC.virtuallyD.actuallyA.othersB.the othersC.otherD.the otherA.getting byB.getting onC.getting throughD.getting overA.evidencesB.picturesC.tracesD.tracksA.popularB.commonC.ordinaryD.widespreadA.showsB.denotesC.indicatesD.hintsA.businessB.comme
8、rcialC.tradingD.exchangingA.greenB.landC.wildD.grownA.createdB.developedC.designedD.formulatedA.largeB.vastC.greatD.bigA.floorB.levelC.groundD.layerA.in turnB.in factC.in returnD.in the endA.offerB.equipC.helpD.provideA.essentialB.importantC.possibleD.inevitableA.in timeB.overtimeC.at timesD.behind
9、timeA.takingB.graspingC.suckingD.catchingA.instead ofB.in spite ofC.in place ofD.by contrast of二、Reading Comprehensio(总题数:10,分数:58.00)2.Section II Reading Comprehension_3.Part ADirections: Read the following four texts. Answer the questions below each text by choosing A, B, C or D._Addiction is such
10、 a harmful behavior, in fact, that evolution should have long ago weeded it out of the population: if it“s hard to drive safely under the influence, imagine trying to run from a saber-toothed tiger or catch a squirrel for lunch, And yet, says Dr. Nora Volkow, director of NIDA and a pioneer in the us
11、e of imaging to understand addiction, “the use of drugs has been recorded since the beginning of civilization. Humans in my view will always want to experiment with things to make them feel good“. That“s because drugs of abuse co-opt the very brain functions that allowed our distant ancestors to sur
12、vive in a hostile world. Our minds are programmed to pay extra attention to what neurologists call saliencethat is, special relevance. Threats, for example, are highly salient, which is why we instinctively try to get away from them. But so are food and sex because they help the individual and the s
13、pecies survive. Drugs of abuse capitalize on this ready-made programming. When exposed to drugs, our memory systems, reward circuits, decision-making skills and conditioning kick insalience in overdriveto create an all consuming pattern of uncontrollable craving. “Some people have a genetic predispo
14、sition to addiction“, says Volkow. “But because it involves these basic brain functions, everyone will become an addict if sufficiently exposed to drugs or alcohol“. That can go for nonchemical addictions as well. Behaviors, from gambling to shopping to sex, may start out as habits but slide into ad
15、dictions. Sometimes there might be a behavior-specific root of the problem. Volkow“s research group, for example, has shown that pathologically obese people who are compulsive eaters exhibit hyperactivity in the areas of the brain that process food stimuliincluding the mouth, lips and tongue. For th
16、em, activating these regions is like opening the floodgates to the pleasure center. Almost anything deeply enjoyable can turn into an addiction, though. Of course, not everyone becomes an addict. That“s because we have other, more analytical regions that can evaluate consequences and override mere p
17、leasure seeking. Brain imaging is showing exactly how that happens. Paulus, for example, looked at drug addicts enrolled in a VA hospital“s intensive four-week rehabilitation program. Those who were more likely to relapse in the first year after completing the program were also less able to complete
18、 tasks involving cognitive skills and less able to adjust to new rules quickly. This suggested that those patients might also be less adept at using analytical areas of the brain while performing decision-making tasks. Sure enough, brain scans showed that there were reduced levels of activation in t
19、he prefrontal cortex, where rational thought can override impulsive behavior. It“s impossible to say if the drugs might have damaged these abilities in the relapsersan effect rather than a cause of the chemical abusebut the fact that the cognitive deficit existed in only some of the drug users sugge
20、sts that there was something innate that was unique to them. To his surprise, Paulus found that 80% to 90% of the time, he could accurately predict who would relapse within a year simply by examining the scans. Another area of focus for researchers involves the brain“s reward system, powered largely
21、 by the neurotransmitter dopamine. Investigators are looking specifically at the family of dopamine receptors that populate nerve cells and bind to the compound. The hope is that if you can reduce the effect of the brain chemical that carries the pleasurable signal, you can loosen the drug“s hold.(分
22、数:10.00)(1).According to Dr. Nora Volkow, the use, of drugs(分数:2.00)A.is a very harmful behavior that evolution failed to get rid of.B.makes it hard for people to drive safely under its influence.C.has to do with people“s desire to achieve pleasant feelings.D.is understandable behavior because it da
23、tes back long ago.(2).According to the text, anyone may be addicted to drugs if they(分数:2.00)A.are born with a predisposition to addiction.B.use certain chemicals long and frequently enough.C.have sufficient drugs or alcohol to use.D.create an all consuming pattern of uncontrollable craving.(3).Comp
24、ulsive eaters are typical example of(分数:2.00)A.pleasure turning into habits and finally addiction.B.obese people with brain hyperactivity.C.those who can“t control their mouth, lips and tongue.D.those who might also be addicted to gambling.(4).Paulus could accurately predict the relapsers because(分数
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