2017年英语职称考试理工类C级阅读十四

2017年英语职称考试理工类C级阅读十四Late-nightdrinkingCoffeeloversbeware.Havingaquick“pick-me-up”cupofcoffeelateinthedaywillplayhavocwithyousleep.Aswellasbeingastimulant,caffeineinterruptstheflowofmelatonin,thebrainhormonethatsendpeopleintoasleep.Melatoninlevelsnormallystarttoriseabouttwohoursbeforebedtime.Levelsthenpeakbetween2a.m.and4a.m,beforefallingagain.“It’stheneurohormonethatcontrolsoursleepandtellsourbodywhentosleepandwhentowake,”saysMauriceOhayonoftheStanfordSleepEpidemiklogyResearchCenteratStanfordUniversityinCalifornia.ButresearchersinIsraelhavefoundthatcaffeinatedcoffeehalvesthebody’slevelsofthissleephormone.LotanShiloandateamattheSapirMedicalCenterinTelAvivUniversityfoundthatsixvolunteerssleptlesswellafteracupofcaffeinatedcoffeethanafterdrinkingthesameamountofdecaf.Onaverage,subjectsslept336minutespernightafterdrinkingcaffeinatedcoffee,comparedwith415minutesafterdecaf.Theyalsotookhalfanhourtodropoff---twiceaslongasusual---andjiggedaroundintwiceasmuch..Inthesecondphaseoftheexperiment,theresearcherswokethevolunteerseveythreehousandaskedthemtogiveaurinesample.Shilomeasuredconcentrationsofabreakerswerehalfthoseindecafdrinkers.Theresultssuggestthatmelatoninconcentrationsincaffeinedrinkerswerehalfthoseindecafdrinkers.InapaperacceptedforpublicationinSleepMedicine,theresearcherssuggestthatcaffeineblocksproductionoftheenzymethedrivesmelatoninproduction.Becauseitcantakemanyhourstoeliminatecaffeinefromthebody,Ohayonrecommendsthatcoffeeloversswitchtodecafafterlunch.练习：1.Theauthormentions“pick-me-up”toindicatethatA)melatoninlevelsneedtoberaised.B)Neurohormonecanwakeusup.C)Coffeeisstimulant.D)Decafisacaffeinatedcoffee.2.Whichofthefollowingtellsushowcaffeineaffectssleep?A)Caffeineblocksproductionoftheenzymethatstopsmelatoninproduction.B)Caffeineinterruptstheflowofsleephormone.C)Caffeinehalvesthebody’slevelsofsleephormone.D)Caffeinestaysinthebodyformanyhours.3.Whatdoesparagraph3mainlydiscuss?A)Differenteffectsofcaffeinatedcoffeeanddecafonsleep.B)DifferentfindingsofLotanShiloandateamaboutcaffeine.C)Thefactthatthesubjectsslept415minutespernightafterdrinkingdecaf.D)Theevidencethatthesubjectstookhalfanhourtofallasleep.4.Whatdoestheexperimentmentionedinparagraphinparagraph4prove?A)Therearemoreenzymesindecafdrinkers’urinesample.B)Therearemoremelatoninconcenrrationsincaffeinedrinkers’urinesample.C)Decafdrinkersproducelessmelatonin.D)Caffeinedrinkersproducelesssleephormone.5.TheauthorofthispassageprobablyagreesthatA)coffeeloverssleeplessthanthosewhodonotdrinkcoffee.B)Weshouldnotd