Antarcticahasactuallybecomeakindofspacestationauniqueobservationpostfordetectingimportantchangesintheworld'senvironment.Remotefrommajorsourcesofpollutionandthecomplexgeologicalandecologicalsystemsthatprevailelsewhere,Antarcticamakespossiblescientificmeasurementsthatareoftensharperandeasiertointerpretthanthosemadeinotherpartsoftheworld.
GrowingnumbersofscientiststhereforeseeAntarcticaasadistant-early-warningsensor,wherepotentiallydangerousglobaltrendsmaybespottedbeforetheyshowuptothenorth.Onepromisingfieldofinvestigationisglaciology.ScholarsfromtheUnitedStates,Switzerland,andFrancearepursuingsevenseparatebutrelatedprojectsthatreflecttheirconcernforthehealthoftheWestAntarcticIceSheetaconcerntheybelievetheworldatlargeshouldshare.
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,rippledfieldsofsanddunes,clustersofboulderssculpturedintofantasticshapesby100-mile-an-hourwinds,andanauraofextraterrestrialdesolation.
Despitetheunearthlyaspectofthedryvalleys,somescientistsbelievetheymaycarryamessageofhopeoftheverdantpartsoftheearth.Somescientistsbelievethatinsomecasesthedryvalleysmaysoakuppollutantsfasterthanpollutantsenterthem.
1.Whatisthebesttitleforthispassage?
[A]AntarcticaandenvironmentalProblems.
[B]Antarctica:Earth'sEarly-Warningstation.
[C]Antarctica:aUniqueObservationPost.
[D]Antarctica:aMysteriousPlace.
2.WhatwouldtheresultbeiftheWestAntarcticIceSheetdisappeared?
[A]Thewesternpartofthecontinentwouldbedisappeared.
[B]Thewesternpartofthecontinentwouldbereduced.
[C]ThewesternpartofthecontinentwouldbecomescatteredIslands.
[D]ThewesternpartofthecontinentwouldbereducedtoaclusterofIslands.
3.WhyaretheDryValleysleftbare?
[A]Viciouswindblaststhesnowaway.
[C]Becauseoftheglobalwarmingtrendandfiercewind.
4.Whichofthefollowingistrue?
[A]The"DryValleys"havenothingleftinside.
[B]The"DryValleys"neverheldglaciers.
[C]The"DryValleys"maycarryamessageofhopefortheverdant.
[D]The"DryValleys"areuselesstoscientists.
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