tpo3.docx

tpo3.docx

《tpo3.docx》由会员分享，可在线阅读，更多相关《tpo3.docx（16页珍藏版）》请在冰豆网上搜索。

tpo3

智课网TOEFL备考资料

tpo3阅读文本答案解析+翻译

摘要：

下面是小马过河整理的托福tpo3阅读文本答案解析+翻译，同学们可在线免费下载托福TPO全套试题word或者PDF格式，希望对大家备考托福阅读考试有所帮助。

托福TPO3阅读文本答案解析+翻译:

DepletionoftheOgallalaAquifer

托福tpo3阅读原文

ThevastgrasslandsoftheHighPlainsinthecentralUnitedStatesweresettledbyfarmersandranchersinthe1880s.Thisregionhasasemiaridclimate,andfor50yearsafteritssettlement,itsupportedalow-intensityagriculturaleconomyofcattleranchingandwheatfarming.Intheearlytwentiethcentury,however,itwasdiscoveredthatmuchoftheHighPlainswasunderlainbyahugeaquifer（arocklayercontaininglargequantitiesofgroundwater）.ThisaquiferwasnamedtheOgallalaaquiferaftertheOgallalaSiouxIndians,whoonceinhabitedtheregion.

TheOgallalaaquiferisasandstoneformationthatunderliessome583,000squarekilometersoflandextendingfromnorthwesternTexastosouthernSouthDakota.WaterfromrainsandmeltingsnowshasbeenaccumulatingintheOgallalaforthepast30,000years.EstimatesindicatethattheaquifercontainsenoughwatertofillLakeHuron,butunfortunately,underthesemiaridclimaticconditionsthatpresentlyexistintheregion,ratesofadditiontotheaquiferareminimal,amountingtoabouthalfacentimeterayear.

ThefirstwellsweredrilledintotheOgallaladuringthedroughtyearsoftheearly1930s.Theensuingrapidexpansionofirrigationagriculture,especiallyfromthe1950sonward,transformedtheeconomyoftheregion.Morethan100,000wellsnowtaptheOgallala.Modernirrigationdevices,eachcapableofspraying4.5millionlitersofwateraday,haveproducedalandscapedominatedbygeometricpatternsofcirculargreenislandsofcrops.OgallalawaterhasenabledtheHighPlainsregiontosupplysignificantamountsofthecotton,sorghum,wheat,andcorngrownintheUnitedStates.Inaddition,40percentofAmericangrain-fedbeefcattlearefattenedhere.

Thisunprecedenteddevelopmentofafinitegroundwaterresourcewithanalmostnegligiblenaturalrechargerate—thatis,virtuallynonaturalwatersourcetoreplenishthewatersupply—hascausedwatertablesintheregiontofalldrastically.Inthe1930s,wellsencounteredplentifulwateratadepthofabout15meters;currently,theymustbedugtodepthsof45to60metersormore.Inplaces,thewatertableisdecliningatarateofameterayear,necessitatingtheperiodicdeepeningofwellsandtheuseofever-more-powerfulpumps.Itisestimatedthatatcurrentwithdrawalrates,muchoftheaquiferwillrundrywithin40years.ThesituationismostcriticalinTexas,wheretheclimateisdriest,thegreatestamountofwaterisbeingpumped,andtheaquifercontainstheleastwater.ItisprojectedthattheremainingOgallalawaterwill,bytheyear2030,supportonly35to40percentoftheirrigatedacreageinTexasthatissupportedin1980.

ThereactionoffarmerstotheinevitabledepletionoftheOgallalavaries.Manyhavebeenattemptingtoconservewaterbyirrigatinglessfrequentlyorbyswitchingtocropsthatrequirelesswater.Others,however,haveadoptedthephilosophythatitisbesttousethewaterwhileitisstilleconomicallyprofitabletodosoandtoconcentrateonhigh-valuecropssuchascotton.Theincentiveofthefarmerswhowishtoconservewaterisreducedbytheirknowledgethatmanyoftheirneighborsareprofitingbyusinggreatamountsofwater,andintheprocessaredrawingdowntheentireregion’swatersupplies.

Inthefaceoftheupcomingwatersupplycrisis,anumberofgrandioseschemeshavebeendevelopedtotransportvastquantitiesofwaterbycanalorpipelinefromtheMississippi,theMissouri,ortheArkansasrivers.Unfortunately,thecostofwaterobtainedthroughanyoftheseschemeswouldincreasepumpingcostsatleasttenfold,makingthecostofirrigatedagriculturalproductsfromtheregionuncompetitiveonthenationalandinternationalmarkets.Somewhatmorepromisinghavebeenrecentexperimentsforreleasingcapillarywater（waterinthesoil）abovethewatertablebyinjectingcompressedairintotheground.Evenifthisprocessprovessuccessful,however,itwouldalmosttriplewatercosts.Geneticengineeringalsomayprovideapartialsolution,asnewstrainsofdrought-resistantcropscontinuetobedeveloped.Whateverthefinalanswertothewatercrisismaybe,itisevidentthatwithintheHighPlains,irrigationwaterwillneveragainbetheabundant,inexpensiveresourceitwasduringtheagriculturalboomyearsofthemid-twentiethcentury.

托福tpo3阅读试题

1.Accordingtoparagraph1,whichofthefollowingstatementsabouttheHighPlainsistrue?

A.Untilfarmersandrancherssettledthereinthe1880s,theHighPlainshadneverbeeninhabited.

B.TheclimateoftheHighPlainsischaracterizedbyhigher-than-averagetemperatures.

C.ThelargeaquiferthatliesunderneaththeHighPlainswasdiscoveredbytheOgallalaSiouxIndians.

D.Beforetheearly1900stherewasonlyasmallamountoffarmingandranchingintheHighPlains.

2.Accordingtoparagraph2,allofthefollowingstatementsabouttheOgallalaaquiferaretrueEXCEPT:

A.TheaquiferstretchesfromSouthDakotatoTexas.

B.Theaquifer’swatercomesfromundergroundsprings.

C.Waterhasbeengatheringintheaquiferfor30,000years.

D.Theaquifer’swaterisstoredinalayerofsandstone.

3.Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthepassage（paragragh2）?

Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.

A.DespitethecurrentimpressivesizeoftheOgallalaaquifer,theregion’sclimatekeepstheratesofwateradditionverysmall.

B.Althoughtheaquiferhasbeenaddingwaterattherateofonlyhalfacentimeterayear,itwilleventuallyaccumulateenoughwateroffillLakeHuron.

C.Becauseoftheregion’spresentclimaticconditions,waterisbeingaddedeachyeartotheaquifer.

D.Evenwhentheregionexperiencesunfortunateclimaticconditions,theratesofadditionofwatercontinuetoincrease.

4.Theword“ensuing”inthepassage（paragraph3）isclosestinmeaningto

A.continuing

B.surprising

C.initial

D.subsequent

5.Inparagraph3,whydoestheauthorprovidetheinformationthat40percentofAmericancattlearefattenedintheHighPlains?

A.TosuggestthatcropcultivationisnotthemostimportantpartoftheeconomyoftheHighPlains

B.ToindicatethatnotalleconomicactivityintheHighPlainsisdependentonirrigation

C.ToprovideanotherexampleofhowwaterfromtheOgallalahastransformedtheeconomyoftheHighPlains

D.Tocontrastcattle-fatteningpracticesintheHighPlainswiththoseusedinotherregionoftheUnitedStates

6.Theword“unprecedented”inthepassage（paragraph4）isclosestinmeaningto

A.difficulttocontrol

B.withoutanyrestriction

C.unlikeanythinginthepast

D.rapidlyexpanding

7.Theword“virtually”inthepassage（paragraph4）isclosestinmeaningto

A.clearly

B.perhaps

C.frequently

D.almost

8.Accordingtoparagraph4,alloffollowingareconsequencesoftheheavyuseoftheOgallalaaquiferforirrigationEXCEPT:

A.Therechargerateoftheaquiferisdecreasing.

B.Watertablesintheregionarebecomingincreasinglylower.

C.Wellsnowhavetobedugtomuchgreaterdepthsthanbefore.

D.Increasinglypowerfulpumpsareneededtodrawwaterfromtheaquifer.

9.Accordingtoparagraph4,comparedwithallotherstatesthatuseOgallalawaterforirrigation,Texas

A.hasthegreatestamountoffarmlandbeingirrigatedwithOgallalawater

B.containsthelargestamountofOgallalawaterunderneaththesoil

C.isexpectedtofacetheworstwatersupplycrisisastheOgallalarunsdry

D.usestheleastamountofOgallalawaterforitsirrigationneeds

10.Theword“inevitable”inthepassage（paragraph5）isclosestinmeaningto

A.unfortunate

B.predictable

C.unavoidable

D.final

11.Paragraph5mentionswhichofthefollowingasasourceofdifficultyforsomefarmerswhotrytoconservewater?

A.CropsthatdonotneedmuchwateraredifficulttogrowintheHighPlains.

B.Farmerswhogrowcropsthatneedalotofwatermakehigherprofits.

C.Irrigatinglessfrequentlyoftenleadstocropfailure.

D.Fewfarmersareconvincedthattheaquiferwilleventuallyrundry.

12.Accordingtoparagraph6,whatisthemaindisadvantageoftheproposedplanstotransportriverwatertotheHighPlains?

A.Theriverscannotsupplysufficientwaterforthefarmer’sneeds.

B.Increasedirrigationcostswouldmaketheproductstooexpensive.

C.Thecostsofusingcapillarywaterforirrigationwillincrease.

D.Farmerswillbeforcedtoswitchtogeneticallyengineeredcrops.

13.Lookatthefoursquaresthatindicatewherethefollowingsentencecouldbeaddedtothepassage.Butevenifuncooperativefarmersweretojoinintheconservationefforts,thiswouldonlydelaythedepletionoftheaquifer.

ThereactionoffarmerstotheinevitabledepletionoftheOgallalavaries.Manyhavebeenattemptingtoconservewaterbyirrigatinglessfrequentlyorbyswitchingtocropsthatrequirelesswater.Others,however,haveadoptedthephilosophythatitisbesttousethewaterwhileitisstilleconomicallyprofitabletodosoandtoconcentrateonhigh-valuecropssuchascotton.Theincentiveofthefarmerswhowishtoconservewaterisreducedbytheirknowledgethatmanyoftheirneighborsareprofitingbyusinggreatamountsofwater,andintheprocessaredrawingdowntheentireregion’swatersupplies.

Inthefaceoftheupcomingwatersupplycrisis,anumberofgrandioseschemeshavebeendevelopedtotr