TPO25阅读(全三篇含答案)托福真题

PAGE/NUMPAGESThesurfaceofMars　ThesurfaceofMarsshowsawiderangeofgeologicfeatures,includinghugevolcanoes-thelargestknowninthesolarsystem-andextensiveimpactcratering.ThreeverylargevolcanoesarefoundontheTharsisbulge,anenormousgeologicareanearMars’sequator.NorthwestofTharsisisthelargestvolcanoofall:OlympusMons,withaheightof25kilometersandmeasuringsome700kilometersindiameteratitsbase.ThethreelargevolcanoesontheTharsisbulgearealittlesmaller-a“mere”18kilometershigh.NoneofthesevolcanoeswasformedasaresultofcollisionsbetweenplatesoftheMartiancrust-thereisnoplatemotiononMars.Instead,theyareshieldvolcanoes-volcanoeswithbroad,slopingslidesformedbymoltenrock.AllfourshowdistinctivelavachannelsandotherflowfeaturessimilartothosefoundonshieldvolcanoesonEarth.ImagesoftheMartiansurfacerevealmanyhundredsofvolcanoes.MostofthelargestvolcanoesareassociatedwiththeTharsisbulge,butmanysmalleronesarefoundinthenorthernplains.　　ThegreatheightofMartianvolcanoesisadirectconsequenceoftheplanet’slowsurfacegravity.Aslavaflowsandspreadstoformashieldvolcano,thevolcano’seventualheightdependsonthenewmountain’sabilitytosupportitsownweight.Thelowerthegravity,thelessertheweightandthegreatertheheightofthemountain.ItisnoaccidentthatMaxwellMonsonVenusandtheHawaiianshieldvolcanoesonEarthrisetoaboutthesameheight(about10kilometers)abovetheirrespectivebases-EarthandVenushavesimilarsurfacegravity.Mars’ssurfacegravityisonly40percentthatofEarth,sovolcanoesriseroughly2.5timesashigh.AretheMartianshieldvolcanoesstillactive?Scientistshavenodirectevidenceforrecentorongoingeruptions,butifthesevolcanoeswereactiveasrecentlyas100millionyearsago(anestimateofthetimeoflasteruptionbasedontheextentofimpactcrateringontheirslopes),someofthemmaystillbeatleastintermittentlyactive.Millionsofyears,though,maypassbetweeneruptions.　　　AnotherprominentfeatureofMars’ssurfaceiscratering.TheMarinerspacecraftfoundthatthesurfaceofMars,aswellasthatofitstwomoons,ispittedwithimpactcratersformedbymeteoroidsfallinginfromspace.AsonourMoon,thesmallercratersareoftenfilledwithsurfacematter-mostlydust-confirmingthatMarsisadrydesertworld.However,Martiancratersgetfilledinconsiderablyfasterthantheirlunarcounterparts.OntheMoon,ancientcraterslessthan100metersacross(correspondingtodepthsofabout20meters)havebeenobliterated,primarilybymeteoriticerosion.OnMars,therearerelativelyfewcraterslessthan5kilometersindiameter.TheMartianatmosphereisanefficienterosiveagent,withMartianwindstransportingdustfromplacetoplaceanderasingsurfacefeaturesmuchfasterthanmeteoriticimpactsalonecanobliteratethem.AsontheMoon,theextentoflargeimpactcratering(i.e.craterstoobigtohavebeenfilledinbyerosionsincetheywereformed)servesasanageindicatorfortheMartiansurface.AgeestimatesrangingfromfourbillionyearsforMars’ssouthernhighlandstoafewhundredmillionyearsintheyoungestvolcanicareaswereobtainedinthisway.　　ThedetailedappearanceofMartianimpactcratersprovidesanimportantpieceofinformationaboutconditionsjustbelowtheplanet’ssurface.Martiancratersaresurroundedbyejecta(debrisformedasaresultofanimpact)thatlooksquitedifferentfromitslunarcounterparts.AcomparisonoftheCopernicuscraterontheMoonwiththe(fairlytypical)craterYutyonMarsdemonstratesthedifferences.Theejectasurroundingthelunarcraterisjustwhatonewouldexpectfromanexplosionejectingalargevolumeofdust,soil,andboulders.■However,theejectaonMarsgivesthedistinctimpressionofaliquidthathassplashedorflowedoutofcrater.■Geologiststhinkthatthisfluidizedejectacraterindicatesthatalayerofpermafrost,orwaterice,liesjustafewmetersunderthesurface.■Explosiveimpactsheatedandliquefiedtheice,resultinginthefluidappearanceoftheejecta.■　Q1Theword“enormous”inthepassageisclosestinmeaningtoA.Important　　B.Extremelylarge　C.Highlyunusual　　D.ActiveQ2Accordingtoparagraph1,OlympusMonsdiffersfromvolcanoesontheTharsisbulgeinthatOlympusMonsA.Hasmorecomplexgeologicfeatures　B.Showslessimpactcratering　　C.Istaller　　D.Wasformedatalatertime　　　Paragraph1　Q3Theword“distinctive”inthepassageisclosestinmeaningtoA.Deep　B.Complex　　C.Characteristic　D.Ancient　　　Q4Accordingtoparagraphs1and2,whichofthefollowingisNOTtrueoftheshieldvolcanoesontheTharsisbulge?　　A.Theyhavebroad,slopingsides.B.TheyaresmallerthanthelargestvolcanoonMars.　C.TheyhavechannelsthatresemblethelavachannelsofvolcanoesonEarth.　　D.Theyareover25kilometerstall.　　Paragraph1and2Q5Theword“roughly”inthepassageisclosestinmeaningto　A.TypicallyB.FrequentlyC.Actually　　D.ApproximatelyQ6Inparagraph3,whydoestheauthorcompareMaxwellMonsonVenustotheHawaiianshieldvolcanoesonEarth?　A.Tohelpexplaintherelationshipbetweensurfacegravityandvolcanoheight　B.ToexplainwhyMars’ssurfacegravityisonly40percentofEarth’s　C.TopointoutdifferencesbetweenthesurfacegravityofEarthandthesurfacegravityofVenus　D.Toarguethattherearemoresimilaritiesthandifferencesbetweenvolcanoesondifferentplanets　　　Paragraph3　Q7Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthepassage?Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.　　A.Althoughdirectevidenceofrecenteruptionsislacking,scientistsbelievethatthesevolcanoeswereactiveasrecentlyas100millionyearsago.　B.Scientistsestimatethatvolcanoesactivemorerecentlythan100yearsagowillstillhaveextensiveimpactcrateringontheirslopes.　C.If,assomeevidencesuggests,thesevolcanoeseruptedasrecentlyas100millionyearsago,theymaycontinuetobeintermittentlyactive.　　D.Althoughthesevolcanoeswereactiveasrecentlyas100millionyearsago,thereisnodirectevidenceofrecentorongoingeruptions.　　Q8Theword“considerably”inthepassageisclosestinmeaningtoA.Frequently　B.SignificantlyC.Clearly　D.SurprisinglyQ9Accordingtoparagraph4,whatisdemonstratedbythefactthatcratersfillinmuchfasteronMarsthanontheMoon?　A.ErosionfrommeteoriticimpactstakesplacemorequicklyonMarsthanontheMoon.B.ThereismoredustonMarsthanontheMoon.C.ThesurfaceofMarsisadrydesert.　D.WindisapowerfulerodingforceonMars.　　　Paragraph4　Q10Inparagraph4,whydoestheauthorpointoutthatMarshasfewancientcratersthatarelessthan5kilometersindiameter?A.ToexplainwhyscientistsbelievethatthesurfacematterfillingMartiancratersismostlydust　B.ToexplainwhyscientistsbelievethattheimpactcratersonMarswerecreatedbymeteoroids　　C.TosupporttheclaimthattheMartianatmosphereisanefficienterosiveagent　　D.ToarguethatMarsexperiencedfewerancientimpactsthantheMoondid　Paragraph4Q11Accordingtoparagraph5,whathavescientistsbeenabletodeterminefromstudiesoflargeimpactcrateringonMars?　　A.SomeMartianvolcanoesaremucholderthanwasoncethought.　B.TheageofMars’ssurfacecanvaryfromareatoarea.　　C.Largeimpactcratersarenotreliableindicatorsofageinareaswithhighvolcanicactivity.　D.SomeareasoftheMartiansurfaceappeartobeolderthantheyactuallyare.　　　Paragraph5Q12Accordingtoparagraph6,theejectaofMars’scraterYutydiffersfromtheejectaoftheMoon’sCopernicuscraterinthattheejectaoftheYutycrater　A.HasnowbecomepartofapermafrostlayerB.Containsalargevolumeofdust,soilandboulders　　C.Suggeststhatliquidoncecameoutofthesurfaceatthecratersite　　D.Wasthrownacomparativelylongdistancefromthecenterofthecrater　　Paragraph6ismarkedwithanarrow>　Q13Lookatthefoursquares【■】thatindicatewherethefollowingsentencecouldbeaddedtothepassage.　ThissurfacefeaturehasledtospeculationaboutwhatmaylieunderMars’ssurface.　Wherewouldthesentencebestfit?Clickonasquaretoaddthesentencetothepassage.Q14Directions:Anintroductorysentenceforabriefsummaryofthepassageisprovidedbelow.CompletethesummarybyselectingtheTHREEanswerchoicesthatexpressthemostimportantideasinthepassage.Somesentencesdonotbelonginthesummarybecausetheyexpressideasthatarenotpresentedinthepassageorareminorideasinthepassage.Thisquestionisworth2points.　　Dragyouranswerchoicestothespaceswheretheybelong.Toremoveananswerchoice,clickonit.Toreviewthepassage,clickVIEWNEXT.VolcanoesandimpactcratersaremajorfeaturesofMartiangeology.　A.PlatemotiononMars,onceconsideredtohaveplayednoroleinshapingtheplanet’ssurface,isnowseenasbeingdirectlyassociatedwiththeplanet’searliestvolcanoes.　　B.Marshasshieldvolcanoes,someofwhichareextremelytallbecauseoftheplanet’slowsurfacegravity.　　C.AlthoughtheerosivepoweroftheMartianatmosphereensuresthatMarshasfewercratersthantheMoondoes,impactcratersareprominentonMars’ssurface.　　D.ScientistscannotyetreliablyestimatetheageoftheMartiansurfacebecausetherehasbeentoomucherosionofit.　E.ScientistshavebeensurprisedtodiscoverthatconditionsjustbelowthesurfaceofMarsareverysimilartoconditionsjustbelowthesurfaceoftheMoon　　F.StudiesofcraterejectahaverevealedthepossibilityofalayerofpermafrostbelowthesurfaceofMars.　　　TheDeclineofVenetianShipping　Inthelatethirteenthcentury,northernItaliancitiessuchasGenoa,Florence,andVenicebegananeconomicresurgencethatmadethemintothemostimportanteconomiccentersofEurope.Bytheseventeenthcentury,however,otherEuropeanpowershadtakenover,astheItaliancitieslostmuchoftheireconomicmight.ThisdeclinecanbeseenclearlyinthechangesthataffectedVenetianshippingandtrade.First,Venic’sintermediaryfunctionsintheAdriaticSea,whereithaddominatedthebusinessofshippingforotherparties,werelosttodirecttrading.Inthefifteenthcenturytherewaslittleproblemrecruitingsailorstorowthegalleys(largeshipspropelledbyoars):guilds(businessassociations)wererequiredtoproviderowers,andthroughadraftsystemfreecitizensservedcompulsorilywhencalledfor.█Intheearlysixteenthcenturytheshortageofrowerswasnotseriousbecausethedemandforgalleyswaslimitedbyamovetoroundships(round-hulledshipswithmorecargospace),withrequiredfewerrowers.█Buttheshortageofcrewsprovedtobeagreaterandgreaterproblem,despitecontinuousappealtoVenic’straditionofmaritimegreatness.█Eventhoughsailors’wagesdoubledamongthenorthernItaliancitiesfrom1550to1590,thisdidnotelicitanincreasedsupply█.　　　TheprobleminshippingextendedtotheArsenale,Venice’shugeandpowerfulshipyard.Timberranshort,anditwasnecessarytoprocureitfromfatherandfatheraway.InancientRomantimes,theItalianpeninsulahadgreatforestoffirpreferredforwarships,butscarcitywasapparentasearlyastheearlyfourteenthcentury.ArsenaleofficersfirstbroughttimberfromthefoothillsoftheAlps,thenfromnorthtowardTrieste,andfinallyfromacrosstheAdriatic.Privateshipbuilderswererequiredtobuytheiroakabroad.Asthecostsofshipbuildingrose,VeniceclungtoitsoutdatedstandardwhiletheDutchwereinnovationinthelighterandmoreeasilyhandledships.　　Thestepfrombuyingforeigntimbertobuyingforeignshipswasregardedasashortone,especiallywhencomplaintswereheardinthelattersixteenthcenturythatthestandardsandtraditionsoftheArsenalewererunningdown.Workwasstretchedoutanddonepoorly.Olderworkershadbeenallowedtostopworkahalfhourbeforetheregulartime,andin1601youngerworksleftwiththem.MerchantscomplainedthattheprivilegesreservedforVenetian-builtandownedshipswerefirstextendedtothoseVenetianswhoboughtshipsfromabroadandthentoforeign-builtandownedvessels.HistorianFredericLaneobservesthatafterthelossofshipsinbattleinthelatesixteenthcentury,theshipbuildingindustrynolonghadthecapacitytorecoverthatithaddisplayedatthestartofthecentury.　TheconventionalexplanationforthelossofVenetiandominanceintradeisestablishmentofthePortuguesedirectsearoutetotheEast,replacingtheoverlandSilkRoadfromtheBlackseaandthehighlyprofitableIndianOcean-caravan-easternMediterraneanroutetoVenice.ThePortugueseVascodaGama’sVoyagaaroundsouthernAfricatoIndiatookplaceattheendofthefifteenthcentury,andby1502thetrans-Abrabiancaravanroutehadbeencutoffbypoliticalunrest.　　TheVenetianCouncilfinallyallowedroundshipstoenterthetradethatwaspreviouslyreservedformerchantgalleys,thusreducingtransportcostbyonethird.PricesofspicesdeliveredbyshipfromtheeasternMediterraneancametoequalthoseofspicestransportedbyPaortuguesevessels,buttheincreaseinquantitywithbothroutesinoperationdrovethepricefardown.Gradually,Venice’sroleasastorageanddistributioncenterforspicesandsilk,dyescotton,andgolddecayed,andbytheearlyseventeenthcenturyVenicehadlostitsmonopolyinmarketssuchasFranceandsouthernGermany.　Venetianshippinghadstartedtodeclinefromabout1530-beforetheentryintotheMediterraneanoflargevolumesofDutchandBritishshipping-andwasclearlyoutclassedbytheendofthecentury.AcontemporaryofShakespeare(1564-1616)observedthattheproductivityofItalianshippinghaddeclined,comparedwiththatoftheBritish,becauseofconservatismandlossofexpertise.Moreover,Italiansailorsweredesertingandemigrating,andcaptains,nolongerrecruitedfromtheranksofnobles,wereweakonnavigations.　　ThisdeclinecanbeseenclearlyinthechangesthataffectedVenetianshippingandtrade.First,Venic’sintermediaryfunctionsintheAdriaticSea,whereithaddominatedthebusinessofshippingforotherparties,werelosttodirecttrading.Inthefifteenthcenturytherewaslittleproblemrecruitingsailorstorowthegalleys(largeshipspropelledbyoars):guilds(businessassociations)wererequiredtoproviderowers,andthroughadraftsystemfreecitizensservedcompulsorilywhencalledfor.█Intheearlysixteenthcenturytheshortageofrowerswasnotseriousbecausethedemandforgalleyswaslimitedbyamovetoroundships(round-hulledshipswithmorecargospace),withrequiredfewerrowers.█Buttheshortageofcrewsprovedtobeagreaterandgreaterproblem,despitecontinuousappealtoVenic’straditionofmaritimegreatness.█Eventhoughsailors’wagesdoubledamongthenorthernItaliancitiesfrom1550to1590,thisdidnotelicitanincreasedsupply█.　Paragraph1:1.Theword“resurgence”inthepassageisclosestinmeaningto　　A.transformation　B.comeback　C.program　　D.expansion　　Paragraph2:2.Theword“compulsorily”inthepassageisclosestinmeaningto　　A.forfree　B.foratimeC.byrequirementD.bydesign　3.Accordingtoparagraph2,whichofthefollowingcontributedtothedeclineofVenetianshipping?A.ThelossoftradeinAdriaticSeaB.Themovefromgalleystoroundships　C.Thedecreaseddemandforgalleys　D.Thedoublingofsailor’swages4.Allofthefollowingarementionedinparagraph2aswaysthatVeniceprovidedrowersforitsgalleyEXCEPT　　A.Requiringbusinessassociationstoprovidesailors　　B.RecruitingsailorsfromothercitiesinnorthernItaly　　C.DraftingVenetiancitizensintoservicesasrowers　D.AppealingtothetraditionsofVeniceasa　Paragraph3:　　5.Theword“outdated”inthepassageisclosestinmeaningto　A.strict　　B.enforced　C.improvedD.old-fashioned　6.Accordingtoparagraphs3,whydidthebuildingofshipsinVenetianshipyardsbecomeincreasinglyexpensive?　A.ThewagesofofficersandworkersintheArsenalekeptrisingB.RomanshipyardswereusingalltheavailablefirtreesforthewarshipsC.Thetimberusedintheshipbuildinghadtobebroughtfromfartherandfartheraway　D.Venetianstandardsrequiredthatshipbuildersusetop-qualitymaterials.　7.Allofthefollowingarementionedinparagraph3and4ascontributingtotheproblemsoftheVenetianshipbuildingindustryattheendofthesixteenthcenturyEXCEPTA.ThequalityofworkperformedintheArsenalehaddeclined　B.Venetian–builtshipswereheavyandgenerallyinefficientC.ArsenaleshipbuildersworkedmoreslowlyD.OnlyafewmerchantscontrolledthebuyingandsellingofmostoftheVenetian-builtships　Paragraph4:　　8.Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthepassage?Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.　　A.ThelossofshipsinbattleattheendofthesixteenthcenturyshowedthatVenetianshipbuilderslackedtheskillstheyhadpossessedatthebeginningofthecentury.　B.Venetianshipbuildingfailedtoquicklyreplacetheshipslostinbattleattheendofthesixteenthcenturyasitwouldhavedoneearlierinthecentury.　　C.FredericLanenotedthatVenicelostshipsinbattleattheendofthesixteenthcentury,showingthatVenetianshipbuildingwasnotlongerknownforitsreliability.　　D.Venetianshipbuildinghadbeenknownforitshighqualityofworkatthebeginningofthesixteenthcentury,buttowardtheendofthecenturyVenetianshipswerepoorerinquality.　Paragraph5:　9.Theword“conventional”inthepassageisclosestinmeaningtoA.informalB.logicalC.correctD.usual10.Whydoestheauthormention“VascodaGama’VoyagearoundsouthernAfricatoIndia”inthepassage?A.toindicatehowthePortuguesecametochallengeVenetiandominanceoftradewiththeEast　B.toexplainwhypoliticaltroublesresultedintheclosingoftheusualroutestoIndia　　C.toprovethatVenetianscouldnotsailroundshipsasefficientlyassailorsfromothercountriesdidD.toshowthatVenetianrelianceonroundshipsratherthangalleysprovedtobeweakness　　Paragraph6:　11.Whichofthefollowingcanbeinferredfromparagraph6abouttheVenetianCouncil’sdecisionconcerningtheuseofroundships?　A.ItresultedinareturntoprofitableinluxurygoodsforVenetianmerchants.B.UltimatelyitdidnotrestorethesuperiorityinthespicetradethatVenicehadenjoyedearlier.　C.IteventuallyenabledVenetianmerchantstoincreasethequantityandpriceofthespicestheysoldinEurope.　D.Itmeansalong-awaitedimprovementinthefortunesoftheshipbuildingindustryinVenice.　12.Accordingtoparagraphs6,inthesixteenthcenturythepriceofspicesdeclinedbecause　　A.FranceandGermanyestablishedmonopoliesanddictatedpricesB.VenetianmerchantgalleyscompetedwithVenetianroundshipsforthespicetrade　　C.MorespiceswereavailablebecauseboththeVenetiansandthePortuguesewereimportingthem　　D.Increaseddemandforsilk,dyes,cottonandgoldmeantthatpeoplehadlessmoneytospendonspices.　　Paragraph7:　13.Lookatthefoursquares[█]thatindicatewherethefollowingsentencecouldbeaddedtothepassage.　Theincreaseinrewardstilldidnotattractyoungpeopletothishardlife,andconvictedcriminalsandslaveswerepressedintoservices.　Wherewouldthesentencebestfit?Clickonasquaretoaddthesentencetothepassage.　14.Directions:Anintroductorysentenceforabriefsummaryofthepassageisprovidedbelow.CompletethesummarybyselectingtheTHREEanswerchoicesthatexpressthemostimportantideasinthepassage.Somesentencesdonotbelonginthesummarybecausetheyexpressideasthatarenotpresentedinthepassageorareminorideasinthepassage.Thisquestionisworth2points.ThelossofpowerandprestigeofItaliancitiesbythesixteenthcenturyisclearlyseeninthedeclineofVenetianshipping.　　●　　●●　　AnswerchoicesA.Venetianshipswerefamousforcarryinglargecargoesofspicesandluxurygoodsaroundtheworldinfast,oar-drivengalleys.B.AshortageoftimberforbuildingthetraditionalgalleysandalackofsailorstorowthemmeantalossofVenetianshippingbusiness.　　C.TheVenetianCouncilmadesurethatVenetian-builtand–ownedshipskeptspecialprivilegesintransportingluxurygoodsinandoutofVenice.　D.VenetianroundshipsbringingspicesandsilkfromtheEasthelpeddrivepricesdownsothatordinarypeoplecouldaffordtobuythem　E.Venicefailedtokeepupwithimprovementinshipdesign,andthecostofshipbuildingroseaqualityandefficiencydeclined.F.ThePortuguesedirectsearoutetotheEastadverselyaffectedVenetiantrade,andVenicefellbehindtheDutchandtheBritishinthequalityoftheirshipsandsailingskills.　　　　TheEvolutionaryOriginofPlants　Theevolutionaryhistoryofplantshasbeenmarkedbyaseriesofadaptations.Theancestorsofplantswerephotosyntheticsingle-celledorganismsthatgaverisetoplantspresumablylackedtrueroots,stems,leaves,andcomplexreproductivestructuressuchasflowers.Allofthesefeaturesappearedlaterintheevolutionaryhistoryofplants.Oftoday’sdifferentgroupsofalgae,greenalgaeareprobablythemostsimilartoancestralplants.Thissuppositionstemsfromtheclosephylogenetic(naturalevolutionary)relationshipbetweenthetwogroups.DNAcomparisonshaveshownthatgreenalgaeareplants’closestlivingrelatives.Inaddition,otherlinesofevidencesupportthehypothesisthatlandplantsevolvedfromancestralgreenalgaeusedthesametypeofchlorophyllandaccessorypigmentsinphotosynthesisasdolandplants.Thiswouldnotbetrueofredandbrownalgae.Greenalgaestorefoodasstarch,asdolandplantsandhavecellwallsmadeofcellulose,similarincompositiontothoseoflandplants.Again,thegoodstorageandcellwallmoleculesofredandbrownalgaearedifferent.　　Todaygreenalgaelivemainlyinfreshwater,suggestingthattheirearlyevolutionaryhistorymayhaveoccurredinfreshwaterhabitats.Ifso,thegreenalgaewouldhavebeensubjectedtoenvironmentalpressuresthatresultedinadaptationsthatenhancedtheirpotentialtogiverisetoland-dwellingororganisms.　█Theenvironmentalconditionsoffreshwaterhabitats,unlikethoseofoceanhabitats,arehighlyvariable.█Watertemperaturecanfluctuateseasonallyorevendailyandchanginglevelofrainfallcanleadtofluctuationsintheconcentrationofchemicalinthewateroreventoperiodinwhichtheaquatichabitatdriesup.█Ancientfreshwatergreenalgaemusthaveevolvedfeaturesthatenablethemtowithstandextremesoftemperatureandperiodsofdryness.█Theseadaptationsservedtheirdescendantwellastheyinvadedland.　　Theterrestrialworldisgreennow,butitdidnotstartoutthatway.Whenplantsfirstmadethetransitionashoremorethan400millionyearsago,thelandwasbarrenanddesolate,inhospitabletolife.Fromapl