tpo25阅读全三篇含答案托福真题.docx
- 文档编号:9402306
- 上传时间:2023-02-04
- 格式:DOCX
- 页数:19
- 大小:25.49KB
tpo25阅读全三篇含答案托福真题.docx
《tpo25阅读全三篇含答案托福真题.docx》由会员分享,可在线阅读,更多相关《tpo25阅读全三篇含答案托福真题.docx(19页珍藏版)》请在冰豆网上搜索。
tpo25阅读全三篇含答案托福真题
ThesurfaceofMars
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”inthepassageisclosestinmeaningto
A.Important
B.Extremelylarge
C.Highlyunusual
D.Active
Q2Accordingtoparagraph1,OlympusMonsdiffersfromvolcanoesontheTharsisbulgeinthatOlympusMons
A.Hasmorecomplexgeologicfeatures
B.Showslessimpactcratering
C.Istaller
D.Wasformedatalatertime
Paragraph1
Q3Theword“distinctive”inthepassageisclosestinmeaningto
A.Deep
B.Complex
C.Characteristic
D.Ancient
Q4Accordingtoparagraphs1and2,whichofthefollowingisNOTtrueoftheshieldvolcanoesontheTharsisbulge?
A.Theyhavebroad,slopingsides.
B.TheyaresmallerthanthelargestvolcanoonMars.
C.TheyhavechannelsthatresemblethelavachannelsofvolcanoesonEarth.
D.Theyareover25kilometerstall.
Paragraph1and2
Q5Theword“roughly”inthepassageisclosestinmeaningto
A.Typically
B.Frequently
C.Actually
D.Approximately
Q6Inparagraph3,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”inthepassageisclosestinmeaningto
A.Frequently
B.Significantly
C.Clearly
D.Surprisingly
Q9Accordingtoparagraph4,whatisdemonstratedbythefactthatcratersfillinmuchfasteronMarsthanontheMoon?
A.ErosionfrommeteoriticimpactstakesplacemorequicklyonMarsthanontheMoon.
B.ThereismoredustonMarsthanontheMoon.
C.ThesurfaceofMarsisadrydesert.
D.WindisapowerfulerodingforceonMars.
Paragraph4
Q10Inparagraph4,whydoestheauthorpointoutthatMarshasfewancientcratersthatarelessthan5kilometersindiameter?
A.ToexplainwhyscientistsbelievethatthesurfacematterfillingMartiancratersismostlydust
B.ToexplainwhyscientistsbelievethattheimpactcratersonMarswerecreatedbymeteoroids
C.TosupporttheclaimthattheMartianatmosphereisanefficienterosiveagent
D.ToarguethatMarsexperiencedfewerancientimpactsthantheMoondid
Paragraph4
Q11Accordingtoparagraph5,whathavescientistsbeenabletodeterminefromstudiesoflargeimpactcrateringonMars?
A.SomeMartianvolcanoesaremucholderthanwasoncethought.
B.TheageofMars’ssurfacecanvaryfromareatoarea.
C.Largeimpactcratersarenotreliableindicatorsofageinareaswithhighvolcanicactivity.
D.SomeareasoftheMartiansurfaceappeartobeolderthantheyactuallyare.
Paragraph5
Q12Accordingtoparagraph6,theejectaofMars’scraterYutydiffersfromtheejectaoftheMoon’sCopernicuscraterinthattheejectaoftheYutycrater
A.Hasnowbecomepartofapermafrostlayer
B.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.Studiesofcratere
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- tpo25 阅读 全三篇含 答案 托福
![提示](https://static.bdocx.com/images/bang_tan.gif)