大学英语六级试卷和答案-2003年12月大学英语六级考试试

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1、2003年12月大学英语六级考试试题及参考答案PartIIReadingComprehension(35minutes)Directions:Thereare4passagesinthispart.Eachpassageisfollowedbysomequestionsorunfinishedstatements.ForeachofthemtherearefourchoicesmarkedA),B),C)andD).YoushoulddecideonthebestchoiceandmarkthecorrespondingletterontheAn

2、swerSheetwithasinglelinethroughthecentre.PassageOneQuestions21to25arebasedonthefollowingpassage.Foryears,doctorsadvisedtheirpatientsthattheonlythingtakingmultivitaminsdoesisgivethemexpensiveurine(尿).Afterall,truevitamindeficienciesarepracticallyunheardofinindustrializedcountr

3、ies.Nowitseemsthosedoctorsmayhavebeenwrong.Theresultsofagrowingnumberofstudiessuggestthatevenamodestvitaminshortfallcanbeharmfultoyourhealth.Althoughproofofthebenefitsofmultivitaminsisstillfarfromcertain,thefewdollarsyouspendonthemisprobablyagoodinvestment.Oratleastthat'sthea

4、rgumentputforwardintheNewEnglandJournalofMedicine.Ideally,sayDr.WalterWillettandDr.MeirStampferofHarvard,allvitaminsupplementswouldbeevaluatedinscientificallyrigorousclinicaltrials.Butthosestudiescantakealongtimeandoftenraisemorequestionsthantheyanswer.Atsomepoint,whileresear

5、chersworkonfiguringoutwherethetruthlies,itjustmakessensetosaythepotentialbenefitoutweighsthecost.Thebestevidencetodateconcernsfolate,oneoftheBvitamins.It'sbeenprovedtolimitthenumberofdefectsinembryos(胚胎),andarecenttrialfoundthatfolateincombinationwithvitaminB12andaformofB6als

6、odecreasesthere-blockageofarteriesaftersurgicalrepair.ThenewsonvitaminEhasbeenmoremixed.Healthyfolkswhotake400internationalunitsdailyforatleasttwoyearsappearsomewhatlesslikelytodevelopheartdisease.ButwhendoctorsgivevitaminEtopatientswhoalreadyhaveheartdisease,thevitamindoesn'

7、tseemtohelp.ItmayturnoutthatvitaminEplaysaroleinpreventionbutcannotundoseriousdamage.DespitevitaminC'sgreatpopularity,consuminglargeamountsofitstillhasnotbeenpositivelylinkedtoanygreatbenefit.ThebodyquicklybecomessaturatedwithCandsimplyexcretes(排泄)anyexcess.Themultivitaminsqu

8、estionboilsdowntothis:Doyouneedtowaituntilalltheevidenceisinbeforeyo