阅读 301文档格式.docx

阅读 301文档格式.docx

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VenusandEartharecommonlyregardedastwinplanetsbutnotidenticaltwins.Theyareaboutthesamesize,arecomposedofroughlythesamemixofmaterials,andmayhavebeencomparablyendowedattheirbeginningwithcarbondioxideandwater.However,thetwinsevolveddifferently,largelybecauseofdifferencesintheirdistancefromtheSun.Withasignificantamountofinternalheat,Venusmaycontinuetobegeologicallyactivewithvolcanoes,rifting,andfolding.However,itlacksanysignofahydrologicsystem（watercirculationanddistribution）:

therearenostreams,lakes,oceans,orglaciers.SpaceprobessuggestthatVenusmayhavestartedwithasmuchwaterasEarth,butitwasunabletokeepitswaterinliquidform.BecauseVenusreceivesmoreheatfromtheSun,waterreleasedfromtheinteriorevaporatedandrosetotheupperatmospherewheretheSun’sultravioletraysbrokethemoleculesapart.Muchofthefreedhydrogenescapedintospace,andVenuslostitswater.Withoutwater,VenusbecamelessandlesslikeEarthandkeptanatmospherefilledwithcarbondioxide.Thecarbondioxideactsasablanket,creatinganintensegreenhouseeffectanddrivingsurfacetemperatureshighenoughtomeltleadandtoprohibittheformationofcarbonateminerals.Volcanoescontinuallyventedmorecarbondioxideintotheatmosphere.OnEarth,liquidwaterremovescarbondioxidefromtheatmosphereandcombinesitwithcalcium,fromrockweathering,toformcarbonatesedimentaryrocks.Withoutliquidwatertoremovecarbonfromtheatmosphere,thelevelofcarbondioxideintheatmosphereofVenusremainshigh.

LikeVenus,Earthislargeenoughtobegeologicallyactiveandforitsgravitationalfieldtoholdanatmosphere.UnlikeVenus,itisjusttherightdistancefromtheSunsothattemperaturerangesallowwatertoexistasaliquid,asolid,andagas.Wateristhusextremelymobileandmovesrapidlyovertheplanetinacontinuoushydrologiccycle.HeatedbytheSun,thewatermovesingreatcyclesfromtheoceanstotheatmosphere,overthelandscapeinriversystems,andultimatelybacktotheoceans.Asaresult,Earth’ssurfacehasbeencontinuallychangedanderodedintodelicatesystemsofrivervalleys-aremarkablecontrasttothesurfacesofotherplanetarybodieswhereimpactcratersdominate.FewareasonEarthhavebeenuntouchedbyflowingwater.Asaresult,rivervalleysarethedominantfeatureofitslandscape.Similarly,windactionhasscouredfineparticlesawayfromlargeareas,depositingthemelsewhereasvastsandseasdominatedbydunesorinsheetsofloess（fine-grainedsoildeposits）.ThesefluidmovementsarecausedbygravityflowsystemsenergizedbyheatfromtheSun.Othergeologicchangesoccurwhenthegasesintheatmosphereorwaterreactwithrocksatthesurfacetoformnewchemicalcomponentswithdifferentproperties.AnimportantexampleofthisprocesswastheremovalofmostofEarth’scarbondioxidefromitsatmospheretoformcarbonaterocks.However,ifEarthwerealittleclosertotheSun,itsoceanswouldevaporate.IfitwerefartherfromtheSun,theoceanswouldfreezesolid.Becauseliquidwaterwaspresent,self-replicatingmoleculesofcarbon,hydrogen,andoxygendevelopedlifeearlyinEarth’shistoryandhaverapidlymodifieditssurface,blanketinghugepartsofthecontinentswithgreenery.Lifethrivesonthisplanet,andithelpedcreatetheplanet’soxygen-andnitrogen-richatmosphereandmoderatetemperature.

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Afluidisasubstance,suchasaliquidorgas,inwhichthecomponentparticles（usuallymolecules）canmovepastoneanother.Fluidsfloweasilyandconformtotheshapeoftheircontainers.Thegeologicprocessesrelatedtothemovementoffluidsonaplanet’ssurfacecancompletelyresurfaceaplanetmanytimes.TheseprocessesderivetheirenergyfromtheSunandthegravitationalforcesoftheplanetitself.Asthesefluidsinteractwithsurfacematerials,theymoveparticlesaboutorreactchemicallywiththemtomodifyorproducematerials.Onasolidplanetwithahydrosphereandanatmosphere,onlyatinyfractionoftheplanetarymassflowsassurfacefluids.Yetthemovementsofthesefluidscandrasticallyalteraplanet.ConsiderVenusandEarth,bothterrestrialplanetswithatmosphere.（Paragraph1）

Q1:

Theword“modify”inthepassageisclosetinmeaningto

○obtain

○change

○replace

○absorb

Q2:

Theword“drastically”inthepassageisclosetinmeaningto

○gradually

○permanently

○extensively

○possibly

Q3:

Paragraph1supportsallofthefollowingstatementsaboutfluidsEXCEPT

○Theycanchemicallyreactwithparticlesonaplanet’ssurface.

○Mostoftheirmassdoesnotflowbutremainsinplace.

○Theirmovementscanreshapethesurfaceofcertainkindsofplanets.

○TheirmovementsisdrivenbytheSunandbygravity.

therearenostreams,lakes,oceans,orglaciers.SpaceprobessuggestthatVenusmayhavestartedwithasmuchwaterasEarth,butitwasunabletokeepitswaterinliquidform.BecauseVenusreceivesmoreheatfromtheSun,waterreleasedfromtheinteriorevaporatedandrosetotheupperatmospherewheretheSun’sultravioletraysbrokethemoleculesapart.Muchofthefreedhydrogenescapedintospace,andVenuslostitswater.Withoutwater,VenusbecamelessandlesslikeEarthandkeptanatmospherefilledwithcarbondioxide.Thecarbondioxideactsasablanket,creatinganintensegreenhouseeffectanddrivingsurfacetemperatureshighenoughtomeltleadandtoprohibittheformationofcarbonateminerals.Volcanoescontinuallyventedmorecarbondioxideintotheatmosphere.OnEarth,liquidwaterremovescarbondioxidefromtheatmosphereandcombinesitwithcalcium,fromrockweathering,toformcarbonatesedimentaryrocks.Withoutliquidwatertoremovecarbonfromtheatmosphere,thelevelofcarbondioxideintheatmosphereofVenusremainshigh.（Paragraph2）

Q4:

Theword“prohibit”inthepassageisclosetinmeaningto

○prevent

○speedup

○affect

○encourage

Q5:

Accordingtoparagraph2,whatisonedifferencebetweenEarthandVenus?

○EarthhaslesswaterinitsatmospherethanVenusdoes.

○Earthhasahydrologicsystem,butVenusdoesnot.

○EarthislessgeologicallyactivethanVenusis.

○EarthhasmorecarbondioxidethanVenusdoes.

Q6:

Itcanbeinferredfromparagraph2thatEarthevolveddifferentlythanVenusdidinpartbecause

○therewasmorevolcanicactivityonearlyVenusthanonearlyEarth

○theyreceiveddifferentamountsofsolarenergy

○theirinteriorscontaineddifferentamountsofheat

○theirearlyatmospherecontaineddifferentlevelsofoxygenandnitrogen

Q7:

Accordingtoparagraph2,allofthefollowingplayedaroleinkeepingcarbondioxidelevelshighintheatmosphereofVenusEXCEPT

○thebreakingapartofwatermoleculesbyultravioletrays

○theevaporationofwaterreleasedfromtheplanet’sinterior

○theescapeofhydrogenintospace

○thereleaseofmoleculesfrommeltingmetalssuchaslead

LikeVenus,Earthislargeenoughtobegeologicallyactiveandforitsgravitationalfieldtoholdanatmosphere.UnlikeVenus,itisjusttherightdistancefromtheSunsothattemperaturerangesallowwatertoexistasaliquid,asolid,andagas.Wateristhusextremelymobileandmovesrapidlyovertheplanetinacontinuoushydrologiccycle.HeatedbytheSun,thewatermovesingreatcyclesfromtheoceanstotheatmosphere,overthelandscapeinriversystems,andultimatelybacktotheoceans.Asaresult,Earth’ssurfacehasbeencontinuallychangedanderodedintodelicatesystemsofrivervalleys-aremarkablecontrasttothesurfacesofotherplanetarybodieswhereimpactcratersdominate.FewareasonEarthhavebeenuntouchedbyflowingwater.Asaresult,rivervalleysarethedominantfeatureofitslandscape.Similarly,windactionhasscouredfineparticlesawayfromlargeareas,depositingthemelsewhereasvastsandseasdominatedbydunesorinsheetsofloess（fine-grainedsoildeposits）.ThesefluidmovementsarecausedbygravityflowsystemsenergizedbyheatfromtheSun.Othergeologicchangesoccurwhenthegasesintheatmosphereorwaterreactwithrocksatthesurfacetoformnewchemicalcomponentswithdifferentproperties.Animportantexampleofthisprocesswasthere