12英语四级考试全真模拟卷C下载版Word文件下载.docx

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3.宿舍生活利与弊。

DormitoryLife

PartIIReadingComprehension（SkimmingandScanning）

（15minutes）

Inthispart,youwillhave15minutestogooverthepassagequicklyandanswerthequestionsonAnswerSheet1.Forquestions1-7,choosethebestanswerfromthefourchoicesmarked［A］,［B］,［C］and［D］.Forquestion8-10,completethesentenceswiththeinformationgiveninthepassage.

AnimalsontheMove

Itlookedlikeascenefrom“Jaws”butwithoutthedramaticmusic.Ahugesharkwaslowlyswimmingthroughthewater,itstailswingingbackandforthlikethependulumofaclock.

Suddenlysensitivenerveendingintheshark’sskinpickedupvibrationsofastrugglingfish.Thesharkwasimmediatelytransformedintoadeadly,efficientmachineofdeath.Withmusclestaut,thesharkknifedthroughthewateratarapidspeed.Inaflashthesharkcaughtitsvictim,alargefish,initspowerfuljaws.Then,jerkingitsheadbackandforth,thesharktorehugechunksoffleshfromitsvictimandswallowedthem.Soontheactionwasover.

MovingtoSurvive

Inpursuingitsprey,thesharkdemonstratedinadramaticwaytheimportantroleofmovement,orlocomotion,inanimals.

Liketheshark,mostanimalsusemovementtofindfood.Theyalsouselocomotiontoescapeenemies,findamate,andexplorenewterritories.Themethodsoflocomotionincludecrawling,hopping,slithering,flying,swimming,orwalking.

Humanshavetheaddedadvantageofusingtheirvariousinventionstomoveaboutinjustaboutanykindofenvironment.Automobiles,rockets,andsubmarinestransporthumansfromdeepoceanstoasfarawayasthemoon.However,forotheranimalsmovementcameaboutnaturallythroughmillionsofyearsofevolution.Oneofthemostsuccessfulexamplesofanimallocomotionisthatoftheshark.Itsabilitytoquicklyzeroinonitspreyhasalwaysimpressedscientists.ButittookadetailedstudybyDukeUniversitymarinebiologistsS.A.Wainwright,F.Vosburgh,andJ.H.Hebranktofindouthowthesharksdidit.IntheirstudythescientistsobservedsharksswimminginatankatMarinelandinSaintAugustine,Fla.Moviesweretakenofthesharks’movementsandanalyzed.Studieswerealsomadeofsharkskinandmuscle.

SkinIstheKey

Thebiologistsdiscoveredthattheskinofthesharkisthekeytotheanimal’shighefficiencyinswimmingthroughthewater.Theskincontainsmanyfibersthatcrisscrossliketheinsideofabeltedradialtire.Thefibersarecalledcollagenfibers.Thesefiberscaneitherstoreorreleaselargeamountsofenergydependingonwhetherthefibersarerelaxedortaut.Whenthefibersarestretched,energyisstoredinthemthewayenergyisstoredinthestringofabowwhenpulledtight.Whentheenergyisreleased,thefibersbecomerelaxed.

TheDukeUniversitybiologistshavefoundthatthegreateststretchingoccurswherethesharkbendsitsbodywhileswimming.Duringthebody’sbackandforthmotion,fibersalongtheoutsidepartofthebendingbodystretchgreatly.Muchpotentialenergyisstoredinthefibers.Thisenergyisreleasedwhentheshark’sbodysnapsbacktheotherway.

Asenergyisalternatelystoredandreleasedonbothsidesoftheanimal’sbody,thetailwhipsstronglybackandforth.Thiswhip-likeactionpropelstheanimalthroughthewaterlikealivingbullet.

SourceofEnergy

Whatcausesthefiberstostoresomuchenergy?

InfindingtheanswertheDukeUniversityscientistslearnedthattheshark’ssimilaritytoabeltedradialtiredoesn’tstopwiththeskin.Justasaradialtireisinflatedbypressure,so,too,istheareajustundertheshark’scollagen“radials”.Insteadofairpressure,however,thepressureinthesharkmaybeduetotheforceofthebloodpressingonthecollagenfibers.

Whenthesharkswimsslowly,thepressureonthefibersisrelativelylow.Thefibersaremorerelaxed,andthesharkisabletobenditsbodyatsharpangles.Theanimalswimsthiswaywhenlookingaroundforfoodorjustswimming.However,whenthesharkdetectsanimportantfoodsource,somefantasticinvoluntarychangestakeplace.

Thepressureinsidetheanimalmayincreaseby10times.Thispressurechangegreatlystretchesthefibers,enablingmuchenergytobestored.

Thisenergyisthentransferredtothetail,andthesharkisoff.Therestofthestoryispredictable.

DolphinHasSpeedRecord

Anotherfastmarineanimalisthedolphin.Thisseagoingmammalhasbeenclockedatspeedsof32kilometers（20miles）anhour.Biologistsstudyingthedolphinhavediscoveredthat,liketheshark,theanimal’sefficientlocomotioncanbetracedtoitsskin.Adolphin’sskinismadeupinsuchawaythatitoffersverylittleresistancetothewaterflowingoverit.Normallywhenafishorotherobjectmovesslowlythroughthewater,thewaterflowssmoothlypastthebody.Thissmoothflowisknownaslaminarflow.However,atfasterspeedsthewaterbecomesmoreturbulentalongthemovingfish.Thisturbulencemusesfrictionandslowsthefishdown.

Inadolphintheskinissoflexiblethatitbendsandyieldstothewavinessofthewater.

Thewaves,ineffect,becometuckedintotheskin’sfolds.Thisallowstherestofthewatertomovesmoothlybyinalaminarflow.Whereotheranimalswouldbeslowedbyturbulentwateratrapidspeeds,thedolphincanracethroughthewateratrecordbreakingspeeds.

OtherAnimalsLessEfficient

Notallanimalsmoveasefficientlyassharksanddolphins.Perhapsthegreatestloserinlocomotionefficiencyistheslug.Theslug,whichlookslikeasnailwithoutashell,laysdownaslimytrailoverwhichitcrawls.Itusessomuchenergyproducingtheslimymucusandcrawlingoveritthatamousetravelingthesamedistanceusesonlyonetwelfthasmuchenergy.

Scientistssaythatbecauseoftheslug’sinefficientuseofenergy,itslifestylemustberestricted.Thatis,theanimalsareforcedtoconfinethemselvestosmallareasforobtainingfoodandfindingproperlivingconditions.Havehumanseverbeenfacedwiththiskindofproblem?

1.Accordingtothepassage,asharkcanusemovementtodosomethingexcept______________.

［A］tofindfood

［B］toavoidbeingchasedbyitsenemies

［C］tofindanewplacetolive

［D］toshowitsbraveness

2.Examplesofautomobiles,rocketsandsubmarinesareusedtoshowthat_______________.

［A］humansarethemostcleverlivingcreaturesintheworld

［B］humaninventionsenableustotravelinalmostanykindofenvironment

［C］humansareverysuccessfulininventingtransportationtools

［D］humanscan’tmovelikeotheranimalsinanycircumstances

3.Whatisthekeytotheshark’sswiftlocomotioninwater?

［A］Theskin.［B］Thetail.［C］Themuscle.［D］Thejaw.

4.AccordingtotheDukeUniversityscientists,whendoesthesharkstretchitscollagenfiberstothegreatestextent?

［A］Whenmovingitstailrapidly.

［B］Whenfindingitspreys.

［C］Whenstayingwithoutanymovement.

［D］Whenbendingitsbodyinswimming.

5.Whyistheareajustundertheshark’scollagenfiberssimilartoabeltedradialtire?

［A］Becauseitisalsofullofbloodpressure.

［B］Becauseitisalsofilledofairpressure.

［C］Becauseitisalsoinflatedbypressure.

［D］Becauseitalsocanbeusedagainandagain.

6.Alaminarflowisformedwhenafishswims________________.

［A］slowlythroughthewater［B］rapidlythroughthewater

［C］againstthecurrent［D］atthefastestspeedinwater

7.Consumingtheequalamountofenergyasaslugdoes,amousecantravelaslongasit______________.

［A］onetwelfthtimes.［B］thesame.［C］12times.［D］1.2times.

8.Asharkfindsitspreyby________________.

9.Accordingtothepassage,_______________canbecomparedtothestringofabowforbothofthemstoreenergywhenstretched.

10.Whenthesharkdetectsanimportantfoodsource,__________________________takeplace.

PartIIIListeningComprehension（35minutes）

SectionA

Inthissection,youwillhear8shortconversationsand2longconversations.Attheendofeachconversation,oneormorequestionswillbeaskedaboutwhatwassaid.Boththeconversationandthequestionswillbespokenonlyonce.Aftereachquestiontherewillbeapause.Duringthepause,youmustreadthefourchoicesmarked［A］,［B］,［C］and［D］,anddecidewhichisthebestanswer.ThenmarkthecorrespondingletteronAnswerSheet2withasinglelinethroughthecentre.

11.［A］Hehadfinishedhiswork.［B］Hecamebacktosurprisehiswife.

［C］Hecamebackforlunch.［D］Hecamebacktofetchsomedocument.

12.［A］Atalibrary.［B］Inabus.

［C］Attheairport.［D］Atapostoffice.

13.［A］There’sapaperbythedoor.

［B］Thepapermusthaveblownaway.

［C］Heshouldlookfurtherunderthedesk.

［D］Hecanbuyanotheroneatthecorner.

14.［A］11:

25.［B］11:

40.［C］11:

46.［D］11:

26.

15.［A］Therentistoohigh.

［B］Hecan’taffordthehightaxes.

［C］Hedoesn’twanttoliveinthesuburbs.

［D］It’stoofarawayfromhisoffice.

16.［A］No.Hehastofinishhishomework.

［B］No.Hedoesn’tlikegoingtotheclub.

［C］Yes.He’llgoafterhefinisheshishomework.

［D］Yes.He’llwritehispaperafterhereturns.

17.［A］Shelostherway.［B］Shelostherkeys.

［C］Shelosthercar.［D］Shelostherhandbag.

18.［A］Worriedandfrightened.［B］Veryrelaxed.

［C］Quiteunhappy.［D］Angrywiththeprofessor.

Questions19to22arebasedontheconversationyouhavejustheard.

19.［A］Inaclassroom.［B］Inasnackbar.

［C］Inthedormitory.［D］Inacamerashop.

20.［A］Theman’s