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英语部分专项练习（一）PartIReadingComprehensionDirections:Thereare4readingpassagesinthispart.Eachpassageisfollowedbysomequestionsorunfinishedstatements.ForeachofthemtherearefourchoicesmarkedA.,B.,C.andD.YoushoulddecideonthebestchoiceandmarkthecorrespondingletterontheAnswerSheetwithasinglelinethroughthecenter.Questions1to5arebasedonthefollowingpassage:Ifthesalinityofoceanwaterisanalyzed,itisfoundtovaryonlyslightlyfromplacetoplace.Nevertheless,someofthesesmallchangesareimportant.Therearethreebasicprocessesthatcauseachangeinoceanicsalinity.Oneoftheseisthesubtractionofwaterfromtheoceanbymeansofevaporation—conversionofliquidwatertowatervapor.Inthismanner,thesalinityisincreased,sincethesaltsstaybehind.Ifthisiscarriedtotheextreme,ofcourse,whitecrystalsofsaltwouldbeleftbehind;this,bytheway,ishowmuchofthetablesaltweuseisactuallyobtained.Theoppositeofevaporationisprecipitation,suchasrain,bywhichwaterisaddedtotheocean.Heretheoceanisbeingdilutedsothatthesalinityisdecreased.Thismayoccurinareasofhighrainfallorincoastalregionswhereriversflowintotheocean.Thussalinitymaybeincreasedbythesubtractionofwaterbyevaporation,ordecreasedbytheadditionoffreshwaterbyprecipitationorrunoff.Normally,intropicalregionswherethesunisverystrong,theoceansalinityissomewhathigherthanitisinotherpartsoftheworldwherethereisnotasmuchevaporation.Similarly,incoastalregionswhereriversdilutethesea,salinityissomewhatlowerthaninotheroceanicareas.Athirdprocessbywhichsalinitymaybealteredisassociatedwiththeformationandmeltingofseaice.Whenseawaterisfrozen,thedissolvedmaterialsareleftbehind.Inthismanner,seawaterdirectlybeneathfreshlyformedseaicehasahighersalinitythanitdidbeforetheiceappeared.Ofcourse,whenthisicemelts,itwelltendtodecreasethesalinityofthesurroundingwater.IntheWeddellSea,offAntarctica,thedensestwaterintheoceansisformedasaresultofthisfreezingprocess,whichincreasesthesalinityofcoldwater.Thisheavywatersinksandisfoundinthedeeperportionsofoceansoftheworld.1.Whatisthemaintopicofthepassage?A.Wheredowegetourtablesalt?B.OceanicsalinityintropicalregionsC.ThreebasicprocessesthatalteroceanicsalinityD.Variationsofsalinityindifferentpartsoftheocean2.Accordingtotheauthor,theoceanicsalinityisusuallylowerin_____.A.tropicalregionsB.coastalregionsC.placesinwhichwarmcurrentsandcoldcurrentsmeetD.theAntarctica3.Allofthefollowingareprocessesthatdecreaseoceansalinityexcept_____.A.precipitationB.runoffC.meltingD.evaporation4.Whatdoestheword“subtractioninthefourthlineofthefirstparagraphmean?A.reductionB.influxC.transformationD.freezing5.WhichofthefollowingisNOTaresultoftheformationoficeinoceans?A.Thesurroundingwatersinks.B.Thewaterbecomesdenser.C.Watersalinitydecreases.D.Thesurroundingwaterbecomescolder.Questions6to10arebasedonthefollowingpassage:Morethanacenturyago,therelationshipbetweenglacialiceandtheamountofwaterintheoceanbasinswasfirstseen.Whenthegreaticesheetcoveredvastlandareas,thesealevelwasloweredbecausethenormalreturnofwaterfromlandtotheoceanwasreduced.Asaresult,thesealevelroseasIceAgeglaciersmeltedallowingthemeltedwaterstoflowintotheocean.Ifalltheglacialiceonthesurfaceoftheearthtodayshouldmelt,thesealevelmightrisebymorethan150feet.Shorelinevariationsarealsoproducedthroughelevationordepressionoftheland.Duringtimesofglacierformationsthegreatweightoftheiceslowlydepressedtheearth'scrust.Removaloftheweightthroughglaciermeltingallowedtheslowreturnofthecrusttoitsformerposition.ChangesintheGreatIceclimatesfromcoolandwettowarmanddryproducedclimatechangesfarfromtheglaciatedarea.Forexample,attimesofcool-wetglacialclimates,levelsofinlandlakesrose,incontrasttothedepressionofsealevel.Duringthewarm-dryinterglacialclimates,lakelevelswerelowered.TheancientlakeBonneville,largestoftheglaciallakesinWesternUnitedStates,oncecoveredmorethan20,000squaremiles.Ithadamaximumdepthofmorethan1,000feet.GreatSaltLakeinUtahistheshrunkenremnantofthisoncelargelake.Althoughthefirsttimethatearlymanwalkedontheearthisuncertain,heislargelyaproductoftheGreatIceAge.Presentinformationshowsthatduringthistimeheevolvedrapidlybothphysicallyandculturally.HismostprimitivetoolsandskeletalremainshavebeenfoundinsomeoftheoldestdepositscontemporarywiththeGreatIceAgeinAfrica,AsiaandEurope.Theseareoftenassociatedwithremainsofextinctanimals.Withthedisappearanceofthegreaticesheets,theBronzeandIronAgeculturesevolved.Aboutthistimemanyanimalssuitedtocoolerclimatesdied.Althoughmuchremainstobelearned,thestoryoftheGreatIceAgeisbeingunfoldedthroughtheeffortsofspecialistsinmanyfields.Recordingfieldobservation,newtheoriesandmethods,andworldwidestudiesofexistingglaciersarebringingaclearerunderstandingoftheGreatIceAge.6.WhichofthefollowingisNOTimpliedinthepassage?A.ManhasalotmoretolearnabouttheGreatIceAge.B.Theartofmakingtoolswasinstrumentalinbringingabouttheevolutionofhumanbrain.C.ManyspecieswerenotsuitedtothewarmerclimatesoftheBronzeandIronAge.D.Therelationshipbetweenglacialiceandtheamountofwaterintheoceanbasinswasnotseenuntilmorethanahundredyearsago.7.Accordingtothearticle,whichofthefollowingwillinducethedepressionofsealevel?A.formationo