2008年12月20日大学英语六级A卷真题满分答案.doc

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1、·2008年12月20日大学英语六级A卷真题满分答案·PartIwriting(30minutes)注意：此部分试题在答题卡1上PartIIReadingComprehension(Skimmingandscanning)(15minutes)SupersizesurpriseAskanyonewhythereisanobesityepidemicandtheywilltellyouthatit’saldowntoeatingtoomuchandburningtoofewcalories.Thatexplanationappealstocommonsenseandhasdom

2、inatedeffortstogettotherootoftheobesityepidemicandreverseit/yetobesityresearchersareincreasinglydissatisfiedwithit.Manynowbelievethatsomethingelsemusthavechangedinourenvironmenttoprecipitate(促成)suchdramaticrisesinobesityoverthepast40yearsorso.Nobodyissayingthatthe“bigtwo”–reducedphysicalact

3、ivityandincreasedavailabilityoffood–arenotimportantcontributorstotheepidemic,buttheycannotexplainitall.Earlierthisyearareviewpaperby20obesityexpertssetoutthe7mostplausiblealternativeexplanationsfortheepidemic.Heretheyare.1.      NotenoughsleepItiswidelybelievedthatsleepisforthebrain,nottheb

4、ody.Couldashortageofshut-eyealsobehelpingtomakeusfat?Severallarge-scalestudiessuggesttheremaybealink.Peoplewhosleeplessthan7hoursanighttendtohaveahigherbodymassindexthanpeoplewhosleepmore,accordingtodatagatheredbytheUSNationalHealthandNutritionExaminationSurvey.Similarly,theUSNurses’HealthS

5、tudy,whichtracked68,000womenfor16years,foundthatthosewhosleptanaverageof5hoursanightgainedmoreweightduringthestudyperiodthanwomenwhoslept6hours,whointurngainedmorethanwhosewhoslept7.It’swellknownthatobesityimpairssleep,soperhapspeoplegetfatfirstandsleeplessafterwards.Butthenurses’studysugge

6、ststhatitcanworkintheotherdirectiontoo:sleeplossmayprecipitateweightgain.Althoughgettingfiguresisdifficult,itappearsthatwereallyaresleepingless.In1960peopleintheUSsleptanaverageof8.5hourspernight.A2002pollbytheNationalSleepFoundationsuggeststhattheaveragehasfallentounder7hours,andthedecline

7、ismirroredbytheincreaseinobesity.2.      ClimatecontrolWehumans,likeallwarm-bloodedanimals,cankeepourcorebodytemperaturesprettymuchconstantregardlessofwhat’sgoingonintheworldaroundus.Wedothisbyalteringourmetabolic(新陈代新的)rate,shiveringorsweating.Keepingwa