tpo24.docx

tpo24.docx

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tpo24

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tpo24阅读翻译+答案解析（word版下载）

摘要：

下面是小马过河整理的新托福tpo24阅读翻译+答案解析（word版下载），同学们可在线免费下载托福阅读TPO全套试题，希望对大家备考托福阅读考试有所帮助。

tpo24阅读翻译+答案解析（word版下载）第1篇:

LakeWater

tpo24阅读翻译+答案解析（word版下载）：

托福阅读原文

【1】Wheredoesthewaterinalakecomefrom,andhowdoeswaterleaveit?

Waterentersalakefrominflowingrivers,fromunderwaterseepsandsprings,fromoverlandflowoffthesurroundingland,andfromrainfallingdirectlyonthelakesurface.Waterleavesalakeviaoutflowingrivers,bysoakingintothebedofthelake,andbyevaporation.Somuchisobvious.

【2】Thequestionsbecomemorecomplicatedwhenactualvolumesofwaterareconsidered:

howmuchwaterentersandleavesbyeachroute?

Discoveringtheinputsandoutputsofriversisamatterofmeasuringthedischargesofeveryinflowingandoutflowingstreamandriver.Thenexchangeswiththeatmospherearecalculatedbyfindingthedifferencebetweenthegainsfromrain,asmeasured（ratherroughly）byraingauges,andthelossesbyevaporation,measuredwithmodelsthatcorrectfortheothersourcesofwaterloss.Forthemajorityoflakes,certainlythosesurroundedbyforests,inputfromoverlandflowistoosmalltohaveanoticeableeffect.Changesinlakelevelnotexplainedbyriverflowsplusexchangeswiththeatmospheremustbeduetothenetdifferencebetweenwhatseepsintothelakefromthegroundwaterandwhatleaksintothegroundwater.Notetheword"net":

measuringtheactualamountsofgroundwaterseepageintothelakeandoutofthelakeisamuchmorecomplicatedmatterthanmerelyinferringtheirdifference.

【3】Onceallthisinformationhasbeengathered,itbecomespossibletojudgewhetheralake’sflowismainlyduetoitssurfaceinputsandoutputsortoitsundergroundinputsandoutputs.Iftheformeraregreater,thelakeisasurface-water-dominatedlake;ifthelatter,itisaseepage-dominatedlake.Occasionally,commonsensetellsyouwhichofthesetwopossibilitiesapplies.Forexample,apondinhillycountrythatmaintainsasteadywaterlevelallthroughadrysummerinspiteofhavingnostreamsflowingintoitmustobviouslybeseepagedominated.Conversely,apondwithastreamflowinginoneendandouttheother,whichdriesupwhenthestreamdriesup,isclearlysurfacewaterdominated.

【4】Bywhatevermeans,alakeisconstantlygainingwaterandlosingwater:

itswaterdoesnotjustsitthere,or,anyway,notforlong.Thisraisesthematterofalake’sresidencetime.Theresidencetimeistheaveragelengthoftimethatanyparticularmoleculeofwaterremainsinthelake,anditiscalculatedbydividingthevolumeofwaterinthelakebytherateatwhichwaterleavesthelake.Theresidencetimeisanaverage;thetimespentinthelakebyagivenmolecule（ifwecouldfollowitsfate）woulddependontherouteittook:

itmightflowthroughaspartofthefastest,mostdirectcurrent,oritmightcircleinabackwaterforanindefinitelylongtime.

【5】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.

【6】Agivenlake’sresidencetimeisbynomeansafixedquantity.Itdependsontherateatwhichwaterentersthelake,andthatdependsontherainfallandtheevaporationrate.Climaticchange（theresultofglobalwarming?

）isdramaticallyaffectingtheresidencetimesofsomelakesinnorthwesternOntario,Canada.Intheperiod1970to1986,rainfallintheareadecreasedfrom1,000millimetersto650millimetersperannum,whileabove-averagetemperaturesspeededuptheevapotranspirationrate（therateatwhichwaterislosttotheatmospherethroughevaporationandtheprocessesofplantlife）.

【7】Theresulthasbeenthattheresidencetimeofoneofthelakesincreasedfrom5to18yearsduringthestudyperiod.Theslowingdownofwaterrenewalleadstoachainoffurtherconsequences;itcausesdissolvedchemicalstobecomeincreasinglyconcentrated,andthis,inturn,hasamarkedeffectonalllivingthingsinthelake.

tpo24阅读翻译+答案解析（word版下载）：

托福阅读试题

1.ThephraseSomuchinthepassage（paragraph1）refersto

A.thenegativeeffectsofoverlandflow,rain,andevaporationonriverwaterlevels.

B.waterthatalakelosestooutflowingrivers,tothelakebed,andtoevaporation.

C.theimportanceofriverstothemaintenanceoflakewaterlevels.

D.theinformationgivenaboutwaysthatwatercanenterorexitalake.

2.Thewordgainsint