英语等级考试PETS-1考前特别训练英语等级考试PETS-1考前特别训练Youhavetobelieveinyourself.That‘sthesecretofsuccess.以下是小编为大家搜索整理的英语等级考试PETS-1考前特别训练，希望能给大家带来帮助!更多精彩内容请及时关注我们应届毕业生考试网!PassageFourteen(AntarcticaandEnvironment)Antarcticahasactuallybecomeakindofspacestation-auniqueobservationpostfordetectingimportantchangesintheworld’senvironment.Remotefrommajorsourcesofpollutionandthecomplexgeologicalandecologicalsystemsthatprevailelsewhere,Antarcticamakespossiblescientificmeasurementsthatareoftensharperandeasiertointerpretthanthosemadeinotherpartsoftheworld.GrowingnumbersofscientiststhereforeseeAntarcticaasadistant-early-warningsensor,wherepotentiallydangerousglobaltrendsmaybespottedbeforetheyshowuptothenorth.Onepromisingfieldofinvestigationisglaciology.ScholarsfromtheUnitedStates,Switzerland,andFrancearepursuingsevenseparatebutrelatedprojectsthatreflecttheirconcernforthehealthoftheWestAntarcticIceSheet-aconcerntheybelievetheworldatlargeshouldshare.来源：考试大的美女编辑们TheTransantarcticMountain,someofthemmorethan14,000feethigh,dividethecontinentintotwoverydifferentregions.Thepartofthecontinenttothe“east”ofthemountainsisahighplateaucoveredbyanicesheetnearlytwomilesthick.“West”ofthemountain,thehalfofthecontinentsouthoftheAmericasisalsocoveredbyanicesheet,buttheretheicerestsonrockthatismostlywellbelowsealevel.IftheWestAntarcticIceSheetdisappeared,thewesternpartofthecontinentwouldbereducedtoasparseclusterofisland.Whileiceandsnowareobviouslycentraltomanyenvironmentalexperiments,othersfocusonthemysterious“dryvalley”ofAntarctica,valleysthatcontainlittleiceorsnoweveninthedepthsofwinter.SlashedthroughthemountainsofsouthernVictoriaLand,thesevalleysonceheldenormousglaciersthatdescended9,000feetfromthepolarplateautotheRossSea.Nowtheglaciersaregone,perhapsacasualtyoftheglobalwarmingtrendduringthe10,000yearssincetheiceage.Eventhesnowthatfallsinthedryvalleysisblastedoutbyviciouswindsthatroarsdownfromthepolarplateautothesea.Leftbarearespectaculargorges,rippledfieldso