托福TPO24閱讀真題及答案Lake Water

托福TPO24閱讀真題及答案LakeWater托福TPO24閱讀真題及答案LakeWater托福TPO24閱讀真題及答案LakeWaterxxx公司托福TPO24閱讀真題及答案LakeWater文件編號：文件日期：修訂次數(shù)：第1.0次更改批準(zhǔn)審核制定方案設(shè)計(jì)，管理制度以下，是這次環(huán)球托福為正在進(jìn)行托福備考的考友們整理了托福TPO24閱讀真題及答案LakeWater。我們建議考友們，先做真題，后看答案進(jìn)行驗(yàn)證自己的正確率。之后，環(huán)球托福還會(huì)進(jìn)一步推出托福TPO24閱讀真題的做題思路講解分析，做完真題后，更便于提高托福閱讀能力。托福TPO24閱讀真題LakeWaterLakeWaterWheredoesthewaterinalakecomefrom,andhowdoeswaterleaveitWaterentersalakefrominflowingrivers,fromunderwaterseepsandsprings,fromoverlandflowoffthesurroundingland,andfromrainfallingdirectlyonthelakesurface.Waterleavesalakeviaoutflowingrivers,bysoakingintothebedofthelake,andbyevaporation.Somuchisobvious.Thequestionsbecomemorecomplicatedwhenactualvolumesofwaterareconsidered:howmuchwaterentersandleavesbyeachrouteDiscoveringtheinputsandoutputsofriversisamatterofmeasuringthedischargesofeveryinflowingandoutflowingstreamandriver.Thenexchangeswiththeatmospherearecalculatedbyfindingthedifferencebetweenthegainsfromrain,asmeasured(ratherroughly)byraingaugesandthelossesbyevaporation,measuredwithmodelsthatcorrectfortheothersourcesofwaterloss.Forthemajorityoflakes,certainlythosesurroundedbyforests,inputfromoverlandflowistoosmalltohaveanoticeableeffect.Changesinlakelevelnotexplainedbyriverflowsplusexchangeswiththeatmospheremustbeduetothenetdifferencebetweenwhatseepsintothelakefromthegroundwaterandwhatleaksintothegroundwater.Notetheword"net":measuringtheactualamountsofgroundwaterseepageintothelakeandoutofthelakeisamuchmorecomplicatedmatterthanmerelyinferringtheirdifference.Onceallthisinformationhasbeengathered,itbecomespossibletojudgewhetheralake’sflowismainlyduetoitssurfaceinputsandoutputsortoitsundergroundinputsandoutputs.Iftheformeraregreater,thelakeisasurface-water-dominatedlake;ifthelatter,itisaseedominatedlake.Occasionally,commonsensetellsyouwhichofthesetwopossibilitiesapplies.Forexample,apondinhillycountrythatmaintainsasteadywaterlevelallthroughadrysummerinspiteofhavingnostreamsflowingintoitmustobviouslybeseepagedominated.Conversely,apondwithastreamflowinginoneendandouttheother,whichdriesupwhenthestreamdriesup,isclearlysurfacewaterdominated.Bywhatevermeans,alakeisconstantlygainingwaterandlosingwater:itswaterdoesnotjustsitthere,or,anyway,notforlong.Thisraisesthematterofalake’sresidencetime.Theresidencetimeistheaveragelengthoftimethatanyparticularmoleculeofwaterremainsinthelake,anditiscalculatedbydividingthevolumeofwaterinthelakebytherateatwhichwaterleavesthelake.Theresidencetimeisanaverage;thetimespentinthelakebyagivenmolecule(ifwecouldfollowitsfate)woulddependontherouteittook:itmightflowthroughaspartofthefastest,mostdirectcurrent,oritmightcircleinabackwaterforanindefinitelylongtime.Residencetimesvaryenormously.Theyrangefromafewdaysforsmalllakesuptoseveralhundredyearsforlargeones;LakeTahoe,inCalifornia,hasaresidencetimeof700years.TheresidencetimesfortheGreatLakesofNorthAmerica,namely,LakesSuperior,Michigan,Huron,Erie,andOntario,are,respectively,190,100,22,2.5,and6years.LakeErie’sisthelowest:althoughitsareaislargerthanLakeOntario’s,itsvolumeislessthanone-thirdasgreatbecauseitissoshallow-lessthan20metersonaverage.Agivenlake’sresidencetimeisbynomeansafixedquantity.Itdependsontherateatwhichwaterentersthelake,andthatdependsontherainfallandtheevaporationrate.Climaticchange(theresultofglobalwarming)

isdramaticallyaffectingtheresidencetimesofsomelakesinnorthwesternOntario,Canada.Intheperiod1970to1986,rainfallintheareadecreasedfrom1,000millimetersto650millimetersperannum,whileabove-averagetemperaturesspeededuptheevapotranspirationrate(therateatwhichwaterislosttotheatmospherethroughevaporationandtheprocessesofplantlife).Theresulthasbeenthattheresidencetimeofoneofthelakesincreasedfrom5to18yearsduringthestudyperiod.Theslowingdownofwaterrenewalleadstoachainoffurtherconsequences;itcausesdissolvedchemicalstobecomeincreasinglyconcentrated,andthis,inturn,hasamarkedeffectonalllivingthingsinthelake.

托福TPO24閱讀真題LakeWater題目1.ThephraseSomuchinthepassagereferstoA.thenegativeeffectsofoverlandflow,rain,andevaporationonriverwaterlevelsB.waterthatalakelosestooutflowingrivers,tothelakebed,andtoevaporationC.theimportanceofriverstothemaintenanceoflakewaterlevelsD.theinformationgivenaboutwaysthatwatercanenterorexitalake2.ThewordgainsinthepassageisclosestinmeaningtoA.resultsB.increasesC.resourcesD.savings3.Whichofthefollowingcanbeinferredfromparagraph2aboutthemovementofwaterintoalake?A.Heavyrainaccountsformostofthewaterthatentersintolakes.B.Rainfallreplacesapproximatelytheamountofwaterlostthroughevaporation.C.Overlandflowintolakesisreducedbythepresenceofforests.D.Seepagehasasmallereffectonwaterlevelthananyotherinput.4.WhydoestheauthorusethephraseNotetheword"net"inthepassage?A.ToemphasizetheimpactofseepageonwaterlevelsB.TopointoutthatseepageiscalculateddifferentlyfromriverflowsandatmosphericexchangesC.TocomparethedifferentmethodsofcalculatingseepageD.Toemphasizethedifficultyofobtainingspecificvaluesforseepageinputsandoutputs5.ThewordConverselymeaningtoA.ontheotherhandB.inthesamewayC.inotherwordsD.onaverage6.Accordingtoparagraph3,whichofthefollowingbestdescribesaseedominatedlake?A.AlakethatisfedbystreamsbutstillhasfluctuatingwaterlevelsB.AlakewithaconstantwaterlevelthathasnostreamsorriversasinputsC.AlakewithastreamflowingintoitandastreamflowingoutofitD.Alakethathassurfaceandundergroundinputsbutloseswaterduringdryseasons7.Itcanbeinferredfromparagraph4thatthelengthoftimeagivenmoleculeofwaterremainsinalakeA.dependsentirelyupontheaveragespeedofalake'scurrentsB.canbemeasuredbythevolumeofthelakealoneC.canbegreaterorlesserthantheresidencetimeD.issimilartothelengthoftimeallothermoleculesremaininthatlake8.Accordingtoparagraph5,LakeErie'sresidencetimeislowerthanLakeOntario'sforwhichofthefollowingreasons?A.LakeEriehasalargerareathanLakeOntario.B.LakeOntarioisshallowerthanLakeErie.C.LakeOntariohasagreatervolumethanLakeErie.D.LakeEriereceiveslessrainfallthanLakeOntario.9.WhydoestheauthordiscusstheGreatLakesinparagraph5?A.TodemonstratetheextenttowhichresidencetimesvaryfromlaketolakeB.ToillustratehowresidencetimesarecalculatedforspecificlakesC.ToarguethattheresidencetimeofalakeincreaseswithareaD.ToemphasizethatLakeTahoe'sresidencetimeisunusuallylong10.theword“further”inthepassageistheclosestinmeaningtoA.expectedB.additionalC.seriousD.unfortunate11.Accordingtoparagraph6,whichofthefollowingexplainstheincreaseinresidencenorthwesternOntario?A.Theamountofwaterflowingintothelakeshasincreased.B.Therateofevaporationhasdecreasedmoresharplythantheamountofrainfall.C.Therenewalofthelakes'waterhasslowedduetochangesinclimate.D.Plantshaverequiredlesswaterfromthelakes.12.Accordingtoparagraph6,residencetimeisaffectedbyallofthefollowingEXCEPTA.amountofrainfallB.rateofevaporationC.temperatureofsurroundingairD.concentrationofchemicalsinlakewater13.LookatthefoursquaresIIIthatindicatewherethefollowingsentencecouldbeaddedtothepassage.Ofcourse,alakemaybeneithersurface-water-norseedominatedif,forexample,itsinputsarepredominantlysurfaceanditsoutputsarepredominantlyseepage.14.Directions:Anintroductorysentenceforabriefsummaryofthepassageisprovidedbelow.CompletethesummarybyselectingtheTHREEanswerchoicesthatexpressthemostimportantideasinthepassage.Somesentencesdonotbelonginthesummarybecausetheyexpressideasthatarenotpresentedinthepassageorareminorideasinthepassage.Thisquestionisworth2points.Waterenters,remains,andeventuallyleavesalakeinavarietyofways.AnswerChoicesA.Bymeasuringthewaterquantitiesateachofalake'si