中国名校英语四级密卷（1）PartⅡReadingComprehension(35minutes)Directions:Thereare4passagesinthispart.Eachpassageisfollowedbysomequestionsorunfinishedstatements.ForeachofthemtherearefourchoicesmarkedA),B),C)andD).YoushoulddecideonthebestchoiceandmarkthecorrespondingletterontheAnswerSheetwithasinglelinethroughthecenter.PassageOneQuestions21to25arebasedonthefollowingpassage.Antarcticahasactuallybecomeakindofspacestation—auniqueobservationpostfordetectingimportantchangesintheworld’senvironment.S1Remotefrommajorsourcesofpollutionandthecomplexgeologicalandecologicalsystemsthatprevailelsewhere,Antarcticamakespossiblescientificmeasurementsthatareoftensharperandeasiertointerpretthanthosemadeinotherpartsoftheworld.GrowingnumbersofscientiststhereforeseeAntarcticaasadistantearlywarningsensor,wherepotentiallydangerousglobaltrendsmaybespottedbeforetheyshowuptothenorth.Onepromisingfieldofinvestigationisglaciology.ScholarsfromtheUnitedStates,Switzerland,andFrancearepursuingsevenseparatebutrelatedprojectsthatreflecttheirconcernforthehealthoftheWestAntarcticIceSheet—aconcerntheybelievetheworldatlargeshouldshare.TheTransantarcticMountain,someofthemmorethan14,000feethigh,dividethecontinentintotwoverydifferentregions.Thepartofthecontinenttothe“east”ofthemountainsisahighplateaucoveredbyanicesheetnearlytwomilesthick.“West”ofthemountain,thehalfofthecontinentsouthoftheAmericasisalsocoveredbyanicesheet,buttheretheicerestsonrockthatismostlywellbelowsealevel.IftheWestAntarcticIceSheetdisappeared,thewesternpartofthecontinentwouldbereducedtoasparseclusterofisland.Whileiceandsnowareobviouslycentraltomanyenvironmentalexperiments,othersfocusonthemysterious“dryvalley”ofAntarctica,valleysthatcontainlittleiceorsnoweveninthedepthsofwinter.SlashedthroughthemountainsofsouthernVictorialand,thesevalleysonceheldenormousglaciersthatdescend9,000feetfromthepolarplateautotheRossSea.Nowtheglaciersaregone,perhapsacasualtyoftheglobalwarmingtrendduringthe10,000yearssincetheiceage.Eventhesnowthatfallsinthedryvalleysisblastedoutbyviciouswindsthatroardownfromthepolarplateautothesea.Leftbarearespectaculargorges,rippledfieldsofsanddunes,clustersofboulders(大圆石)sculpturedintofantasticshapesby100mileanhourwinds,andanauraofextraterrestrialdesolation.Despitetheunearthlyaspectofthedryvalleys,somescientistsbelievethattheymaycarryamessageofhopefortheverdant(草木繁茂的)partsoftheearth.Somescientistsbelievethatinsomecasesthedryvalleysmaysoakuppollutantsfasterthanpollutantsenterthem.21.Antarcticaisscientificallyimportantinthat____.A)itisaspacestationB)itisanidealplacefortheinvestigationofglaciologyC)thereisthemysteriousdryvalleyD)itcanhelppeopledetectglobalenvironmentalchanges22.Thereasonforthedisappearanceofglaciersinthedryvalleyis____.A)thatthey’vedesendedtotheRossseaB)thatthey’vebeenblastedoutbyviciouswindsC)theglobalwarmingtrendeversincetheiceageD)thatthey’vebeenchangedintogorges,sanddunesandboulders23.WhentheauthorcallsAntarctica“distantearlywarningsen---本文来源于网络，仅供参考，勿照抄，如有侵权请联系删除---sor”,heactuallymeansthat____.A)suchequipmenthasbeensetupforscientificpurposeB)theresearchgroupstherearelikesuchkindofsensorsC)potentialglobalchangescanbeseenonAntarcticafirstD)Antarcticaisremotefromotherpartsoftheearth24.Whichof...