托福TPO阅读49原文.docx

托福TPO阅读49原文.docx

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托福TPO阅读49原文

托福TPO阅读49原文+题目+答案

托福TPO阅读49原文（第一篇）-MatingSongsofFrogs

　　Thecallingorsingingoffrogsplaysanimportantroleintheirreproduction—specifically,inhelpingindividualsfindandselectmates.Soundhasmanyadvantagesasacommunicationsignal.Whensoundsarebroadcast,theauditoryreceptorsdonotneedtobeinaparticularorientationrelativetothesoundsourceinordertoreceivestimulation.Loudsongs,particularlythosemadebychorusesoffrogscallingtogether,cantravellongdistancesandthusattractdistantfrogs.Soundstravelaroundlargeobstacles.Theseadvantagesarenotfoundinthevisualmodality,wherethereceivermustbeattentiveandhaveitsvisualreceptororientatedinthecorrectdirection.Further,mostfrogsandtoadsbreedatnight,whenlightlevelsarelowbutsoundscanbeeasilylocalized.Wecanconcludethatauditorysignalsareusedbyfrogsandtoadsbecausetheycanbeeffectiveoverlongdistancesatnight.

　　Malefrogsdomostofthecourtshipcalling.Othermalefrogscanrespondbyaddingtheirvoicestoformacallingchorus.Malefrogscanalsovocalizetoeachotheraspartofaggressivedisplays.Aggressivecallscanbedistinctfromtheadvertisementcallsusedtoattractfemales.Femalescanrespondtomalesongsbymovingtowardthesoundsourceorbyselectingcertainmalesasreproductivepartners.Insomespeciesfemalesalsorespondtomalesbycalling:

receptivepairscanevenperformduets.Predatorsmayalsocueinoncallingfrogsaspotentialprey.Frogsongscontainseveralpotentiallyimportantpiecesofinformationaboutthecallingmale.First,soundamplitudecanindicatethesizeoftheindividualthatisGalling.Sincemanyfrogsexhibitindeterminategrowth（i.e.,theykeepgettingbiggerastheygetolder）,sizeisagoodpredictorofrelativeage.Inmanyspecies,callamplitudeisincreasedbyspecializedvocalsacsthatcanenlargeastheanimalgrows;thus,olderfrogsproduceloudercalls.Themale’sagematterstothefemalebecauseolderfrogshavesuccessfullysurvivedtheenvironmentalhazardsthattheoffspringtheysirewillsoonbefacing.Amplitudecanalsoconveyinformationonhowfarawaythecallingfrogisor,forchoruses,howmanyfrogsarecallingtogether.Anintenselyvocalizingchorusmayindicateaparticularlyfavorablebreedingsite.Soundamplitude（subjectively:

loudness）canbeanambiguouscueforafemale,however.Averyintensesoundcanindicateanoldmaleatsomedistanceorayoungermalethatisclose.Aclose,smallchoruscouldbeconfusedwithalouderchorusthatisfartheraway.

　　Soundfrequencies-orpitch-canalsoconveyinformationaboutthecallingmalebecausethevocalapparatusgrowslargerasthefroggrowsolder.Insomefrogs,thepitchofindividualsoundsvarieswithsothatolderandlargermalesgivelower-pitchedcalls.Soundpitchisaffectedbytemperature;smallmalescanmimicthelowerpitchoflarger,oldermalesbycallingfromcolderlocations.Finally,thelengthoftimethatanindividualcanaffordtospendcallingisagoodindicatorofhishealth.Manyfrogsinvestconsiderableenergyincalling,bothbecausetheydonotfeedandbecauseitisaphysicallydemandingbehaviorthatreliesonrapidmuscularcontractionsofthevocalizationapparatus.Thiseffortcanbedebilitatinginamalefrogthatisnotintopphysicalcondition.Callingintreefrogsissaidtobethemostenergeticallyexpensivebehavioryetmeasuredanyvertebrate.

　　Soundfrequenciesandtheoveralltemporalpattern（rhythmandrate）ofthesongcanalsorevealthespeciesofthecallingmale.Thefrequenciessoundsandtheirtemporalpatternsarespeciesspecific.Thespeciesofapotentialmateisextremelyimportanttothefemale.Femalesthatchoosetomatewithmembersofanotherspeciesrisklosingtheenergyinvestineggsbecausethehybridoffspringwillnotsurviveandreproduce.

　　Thucomplexityofafrogsongcanalsoaffecthowattractiveitistoafemale.Thesongsofmaletungarafrogs,forexample,canconsistsimplyofshorthigh-frequency“whines”orbyseverallower-frequency"chucks."Morefemalesapproachloudspeakersplayingwhinespluschucksthanwhinesalone.Theadditionofchucks,however,alsohasthedisadvantageofattractingbatsthateatthefrogs.

   托福TPO阅读49原文+题目：

　　1.Accordingtoparagraph1,allofthefollowingarementionedastrueofthematingcallsoffrogs

　　EXCEPT:

　　A.Theycanreachfrogsinfar-offlocations.

　　B.Theyarenotblockedbyobjectsofsubstantialsize.

　　C.Theyareoftencombinedwithnon-auditorysignals.

　　D.Theyerrbereceivedwithoutthefrog’sneedingtoorientitselftowardthedirectionofthesignal.

　　2.Theauthorprovidesinformationabout"thevisualmodality"inorderto

　　A.emphasizethatvisualinformationplaysasignificantpartinfrogbreeding

　　B.explainwhysomefrogsbreedatnight,whileothersbreedduringtheday

　　C.indicatetheresourcefulnesswithwhichfrogsovercomeobstaclesinsoundtravelduringthebreedingprocess

　　D.arguethatauditorysignalshaveadvantagesovervisualsignalsforfrogreproduction

　　3.Theword"potential"inthepassageisclosestinmeaningto

　　A.occasional

　　B.possible

　　C.easy

　　D.hidden

　　4.Theword"favorable”inthepassageisclosestinmeaningto

　　A.wellpopulated

　　B.distant

　　C.extensive

　　D.advantageous

　　5.Accordingtoparagraph3，femalefrogswholistentofrogsongsaretryingtodeterminewhetherafuturemate

　　A.canprotectfutureoffspringfrompredators

　　B.hasanimportantsocialpositionwithinthemalechorus

　　C.hasreachedanagethatindicatestheabilitytosurviveenvironmentalchallenges

　　D.isyoungenoughtobeabletoproducemanyoffspring

　　6.Itcanbeinferredfromparagraph3thatfemalefrogsareseekingmateswho

　　A.caninhabitavarietyofbreedingsites

　　B.canoccupyhabitatsatadistancefromthoseofyoungermalefrogs

　　C.haveprotectedpreviousmatesfromenvironmentalhazards

　　D.arelikelytopassontraitsthatstrengthentheiroffspring'schancesofsurvival

　　7.Theword"ambiguous"inthepassageisclosestinmeaningto

　　A.unexpected

　　B.unclear

　　C.important

　　D.unhelpful

　　8.Theword"convey"inthepassageisclosestinmeaningto

　　A.transmit

　　B.addto

　　C.amplify

　　D.correct

　　9.Paragraph4impliesthatyoungfrogsmaycallfromcoldareasforwhichofthefollowingreasons?

　　A.Toindicatesuperiorstrengthoveroldermales

　　B.Toappearmoreattractivetofemalesbysoundingolderthanactuallyare

　　C.Tobeabletospendlessenergyinproducingtheircall

　　D.Tocompeteagainstfewermalesforafemale’sattention

　　10.Inparagraph4,whydoestheauthormentionthattreefrogcallingissaidtobe“themostenergeticallyexpensivebehavioryetmeasuredinanyvertebrate"?

　　A.explainwhyitisimportantfortreefrogstobeintopphysicalcondition

　　B.Todistinguishtreefrogsfromotherspeciesoffrogs

　　C.Toindicatethatsurvivalismoredifficultforfrogsthanforothervertebrates

　　D.Toemphasizehowphysicaleffortcallingrequires

　　11.Itcanbeinferredparagraph5thathavingspeciesspecificsongsbenefitsfrogsinwhichofthefollowingways?

　　A.Itenablesfrogstobetterprotecteggsfrombeingdamagedbymembersofotherspecies.

　　B.Itmakeitpossibleforfrogstojudgetheirdistancefrompotentialmates.

　　C.Ithelpsfrogstoavoidhavingoffspringthatcannotsurviveandreproduce

　　D.Itmakesitpossibleforfrogstoinvestmoreoftheirenergyintoproducingeggs.

　　12.Accordingtoparagraph6,tungarafrogsaddachucksoundtotheircallinorderto

　　A.makethemselvesmoreattractivetofemales

　　B.keeppredatorsatasafedistance

　　C.attractfrogsofdifferentspecies

　　D.increasetheloudnessoftheircalls

　　13.Lookatthefoursquares■thatindicatewherethefollowingsentencecouldbeaddedtothepassage.

　　Butafrog’sageisnottheonlyinfluenceonthepitchofafrog’scall.

　　Wherewouldthesentencebestfit?

　　■Soundfrequencies-orpitch-canalsoconveyinformationaboutthecallingmalebecausethevocalapparatusgrowslargerasthefroggrowsolder.■Insomefrogs,thepitchofindividualsoundsvarieswithsothatolderandlargermalesgivelower-pitchedcalls.■Soundpitchifaffectedbytemperature;smallmalescanmimicthelowerpitchoflarger,oldermalesbycallingfromcolderlocations.■Finally,thelengthoftimethatanindividualcanaffordtospendcallingisagoodindicatorofhishealth.Manyfrogsinvestconsiderableenergyincalling,bothbecausetheydonotfeedandbecauseitisaphysicallydemandingbehaviorthatreliesonrapidmuscularcontractionsofthevocalizationapparatus.Thiseffortcanbedebilitatinginamalefrogthatisnotintopphysicalcondition.Callingintreefrogsissaidtobethemostenergeticallyexpensivebehavioryetmeasuredanyvertebrate.

　　14.Directions:

Anintroductorysentenceforabriefsummaryofthepassageisprovidedbelow.CompletethesummarybyselectingtheTHREEanswerchoicesthatexpressthemostimportantideasinthepassage.Somesentencesdonotbelonginthesummarybecausetheyexpressideasthatarenotpresentedinthepassageorareminorideasinthepassage.Thisquestionisworth2points.

　　Thecallingorsingingoffrogsisaformofcommunication.

　　1.Forfrogsandtoads,soundhasanumberofadvantagesovervisualsignalsasamediumofcommunicationoverlongdistancesatnight.

　　2.Callingisperformedprimarilybymalefrogstoattractmatesforreproductionandtoactivelycompetewithothermalefrogsforfemales.

　　3.Dependingonthespecies,femalefrogscanobtaininformationfromamale’ssongaboutage,health,andspeciesof