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>>(点击进入下载区)Directions:Inthefollowing text, some sentences have been removed. ForQuestions41-45, choose the most suitable one from the list A-G tofit intoeach of numbered blanks. There are two extra choices, whichdo notfit in any of the blanks. Mark your answers on ANSWER SHEET1. (10points)

Researchers have found that genes play a large role in shapingachild’s emotional makeup, but a child’s personality traits arealsoprofoundly affected by his or her environment. Geneticandenvironmental factors combine in complex ways to shape achild’spsychological development.

The wizards of genetics keep closing in on the biological rootsofpersonality. It’s not your imagination that one baby seemsborncheerful and another morose. But that’s not the completepicture.(41) ___________________________.

In the last few years scientists have identified genes thatappearto predict all sorts of emotional behavior, from happinesstoaggressiveness to risk-taking. (42) __________________. Buttheanswer may not be so simple after all. Scientists are beginningtodiscover that genetics and environment work together todeterminepersonality as intricately as Astaire and Rogers danced.Natureaffects nurture affects nature and back and forth. Eachstepinfluences the next.

(43) ___________________________. An aggressive toddler, underthetight circumstances, can essentially be rewired to channelhisenergy more constructively. A child can overcomehershyness—forever. No child need be held captive to hergeneticblueprint. The implications for child rearing—and socialpolicy—areprofound.

While Gregor Mendel’s pea plants did wonders to explain howhumansinherit blue eyes or a bald spot, they turn out to be aninferiormodel for analyzing something as complex as the brain.(44)___________________________. Genes control thebrain’sneurotransmitters and receptors, which deliver and acceptmentalmessages like so many cars headed for their assignedparkingspaces. But there are billions of roads to each parking lot,andthose paths are highly susceptible to environmental factors.

(45) ___________________________.Children conceived duringathree-month famine in the Netherlands during a Nazi blockadein1945 were later found to have twice the rate of schizophreniaasdid Dutch children born to parents who were spared the traumaoffamine. “Twenty years ago, you couldn’t get your research fundedifyou were looking for a genetic basis for schizophrenia,becauseeveryone knew it was what your mother did to you in thefirst fewyears of life, as Freud said,” says Robert Plomin, ageneticist atLondon’s Institute of Psychiatry. “Now you can’t getfunded unlessyou’re looking for a genetic basis. Neither extreme iscenter, andthe data show why. There’s only a 50 percent concordancebetweengenetics and the development of schizophrenia.”［A］Manyscientistsnow believe that some experiences can actually alter thestructureof the brain.［B］Meanwhile, genetic claims are being madefor a hostof ordinary and abnormal behaviors, from addiction toshyness andeven to political views and divorce. If who we are isdeterminedfrom conception, then our efforts to change or toinfluence ourchildren may be futile. There may also be no basis forinsistingthat people behave themselves and conform to laws. Thus,therevolution in thinking about genes has monumental consequencesforhow we view ourselves as human beings.［C］DNA is notdestiny;experience plays a powerful role, too.［D］A gene is onlyaprobability for a given trait, not a guarantee. For that traittobe expressed, a gene often must be “turned on” by an outsideforcebefore it does its job. High levels of stress apparentlyactivate avariety of genes, including those suspected of beinginvolved infear, shyness and some mental illnesses.［E］The humanbody containsabout 100,000 genes, of which 50,000 to 70,000 areinvolved inbrain n.［F］The inextricable interplay between genes andenvironmentis evident in disorders like alcoholism, anorexia, orovereatingthat are characterized by abnormal behaviors. Scientistsspiritedlydebate whether such syndromes are more or lessbiologically driven.If they are mainly biological—rather thanpsychological, social,and cultural—then there may be a geneticbasis for them.［G］Theage-old question of whether nature or nurturedeterminestemperament seems finally to have been decided in favorof MotherNature and her ever-deepening gene pool.

参考答案

：41 C 42 G 43 A 44 E 45 D