2019年托福考试阅读理解模拟练习题及答案

2019年托福考试阅读理解模拟练习题及答案HormonesintheBodyUptothebeginningofthetwentiethcentury,thenervoussystemwasthoughttocontrolallcommunicationwithinthebodyandtheresultingintegrationofbehavior.Scientistshaddeterminedthatnervesran,essentially,onelectricalimpulses.Theseimpulseswerethoughttobetheengineforthought,emotion,movement,andinternalprocessessuchasdigestion.However,experimentsbyWilliamBaylissandErnestStarlingonthechemicalsecretin,whichisproducedinthesmallintestinewhenfoodentersthestomach,eventuallychallengedthatview.Fromthesmallintestine,secretintravelsthroughthebloodstreamtothepancreas.There,itstimulatesthereleaseofdigestivechemicals.Inthisfashion,theintestinalcellsthatproducesecretinultimatelyregulatetheproductionofdifferentchemicalsinadifferentorgan,thepancreas.Suchacoordinationofprocesseshadbeenthoughttorequirecontrolbythenervoussystem;BaylissandStarlingshowedthatitcouldoccurthroughchemicalsalone.ThisdiscoveryspurredStarlingtocointhetermhormonetorefertosecretin,takingitfromtheGreekwordhormon,meaning“toexcite”or“tosetinmotion.”Ahormoneisachemicalproducedbyonetissuetomakethingshappenelsewhere.Asmorehormoneswerediscovered,theywerecategorized,primarilyaccordingtotheprocessbywhichtheyoperatedonthebody.Someglands(whichmakeuptheendocrinesystem)secretehormonesdirectlyintothebloodstream.Suchglandsincludethethyroidandthepituitary.Theexocrinesystemconsistsoforgansandglandsthatproducesubstancesthatareusedoutsidethebloodstream,primarilyfordigestion.Thepancreasisonesuchorgan,althoughitsecretessomechemicalsintothebloodandthusisalsopartoftheendocrinesystem.Muchhasbeenlearnedabouthormonessincetheirdiscovery.Someplaysuchkeyrolesinregulatingbodilyprocessesorbehaviorthattheirabsencewouldcauseimmediatedeath.Themostabundanthormoneshaveeffectsthatarelessobviouslyurgentbutcanbemorefar-reachinganddifficulttotrack：Theymodifymoodsandaffecthumanbehavior,evensomebehaviorwenormallythinkofasvoluntary.Hormonalsystemsareveryintricate.Evenminuteamountsoftherightchemicalscansuppressappetite,calmaggression,andchangetheattitudeofaparenttowardachild.Certainhormonesacceleratethedevelopmentofthebody,regulatinggrowthandform;othersmayevendefineanindividual’spersonalitycharacteristics.Thequantitiesandproportionsofhormonesproducedchangewithage,soscientistshavegivenagreatdealofstudytoshiftsintheendocrinesystemovertimeinthehopesofalleviatingailmentsassociatedwithaging.Infact,somehormonetherapiesarealreadyverycommon.Acombinationofestrogenandprogesteronehasbeenprescribedfordecadestowomenwhowanttoreducemoodswings,suddenchangesinbodytemperature,andotherdiscomfortscausedbylowernaturallevelsofthosehormonesastheyentermiddleage.Knownashormonereplacementtherapy(HRT),thetreatmentwasalsobelievedtopreventweakeningofthebones.AtleastonestudyhaslinkedHRTwithaheightenedriskofheartdiseaseandcertaintypesofcancer.HRTmayalsoincreasethelikelihoodthatbloodclots—dangerousbecausetheycouldtravelthroughthebloodstreamandblockmajorbloodvessels—willform.SomeproponentsofHRThavetemperedtheirenthusiasminthefaceofthisnewevidence,recommendingitonlytopatientswhosesymptomsinterferewiththeirabilitiestolivenormallives.Humangrowthhormonemayalsobegiventopatientswhoaresecretingabnormallylowamountsontheirown.Becauseofthecomplicatedeffectsgrowthhormonehasonthebody,suchtreatmentsaregenerallyrestrictedtochildrenwhowouldbepathologicallysmallinstaturewithoutit.Growthhormoneaffectsnotjustphysicalsizebutalsothedigestionoffoodandtheagingprocess.Researchersandfamilyphysicianstendtoagreethatitisfoolhardytodispenseitincasesinwhichtherisksarenotclearlyoutweighedbythebenefits.27.Thewordengineinthepassageisclosestinmeaningto(A)desire(B)origin(C)science(D)chemical28.Theworditinthepassagerefersto(A)secretin(B)smallintestine(C)bloodstream(D)pancreas29.Thewordspurredinthepassageisclosestinmeaningto(A)remembered(B)surprised(C)invented(D)motivated30.Tobeconsideredahormone,achemicalproducedinthebodymust(A)bepartofthedigestiveprocess(B)influencetheoperationsofthenervoussystem(C)affectprocessesinadifferentpartofthebody(D)regulateattitudesandbehavior31.Theglandsandorgansmentionedinparagraph3arecategorizedaccordingto(A)whetherscientistsunderstandtheirfunction(B)howfrequentlytheyreleasehormonesintothebody(C)whetherthehormonestheysecreteinfluencetheagingprocess(D)whethertheysecretechemicalsintothebloodParagraph3ismarkedwithanarrow[→]32.Thewordkeyinthepassageisclosestinmeaningto(A)misunderstood(B)precise(C)significant(D)simple33.Thewordminuteinthepassageisclosestinmeaningto(A)sudden(B)small(C)changing(D)noticeable34.Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthepassage?Incorrectanswerchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.(A)Mostmoodsandactionsarenotvoluntarybecausetheyareactuallyproducedbytheproductionofhormonesinthebody.(B)Becausetheeffectsofhormonesaredifficulttomeasure,scientistsremainunsurehowfar-reachingtheireffectsonmoodsandactionsare.(C)Whenthebodyisnotproducingenoughhormones,urgenttreatmentmaybenecessarytoavoidpsychologicaldamage.(D)Theinfluenceofm