高三英语限时阅读训练

高三英语限时阅读训练（一）完形填空(共20小题，每小题1分，满分20分)Thesedays,itiscommontosee5-gallonbottlesofwaterbeingsenttohomes.Supermarket41arefilledwithallkindsofbottledwaterfromsimple42bottlescontaining“purespringwater”toexpensiveforeigntypesofmineralwateringlassbottles.InEurope,bottledwaterisas43assoftdrinksareintheUnitedStates.Peoplearenotonlyinterestedinthedifferentchoicesofdrinks,butalsointhetasteofbottledwaterandits44value.Allbottledwatermust45thecontentofthewateronthebottle.Somecompanies46mineralstogivethewaterabettertaste.Butthetermmineralwateris47,becauseallwater—exceptspeciallypurifiedwater—containsminerals.48mustbemadetotellpeopleclearlywhatkindofwaterpeopleareexactlybuying:springwater,mineralwater,orpurifiedwater.Forexample,“springwater”willhavetocomefroma(n)49spring.Manypeoplechoosebottledwater50tapwater,becausethey51thesafetyofpublicdrinkingwater.Somepeopleworryaboutcitywater52.Weneedtopaycloseattentiontothecleanlinessofourdrinkingwater.Thegovernmentshouldberesponsiblefortapwater53.Itshouldbetestedandchecked54.Keepinmindthatbottledwateris55.Inmanycases,youarepayingforwaterthatisnotmuchdifferentfromtapwater.Ifyouarenotsureofthesafetyofyourtapwater,haveit56.Alocalhealthdepartmentcanbeof57.Comparedwiththecostofbottledwater,thetestingcostwillbelessexpensive.Lettingcoldwater58foraminuteorsobeforetakingadrinkorusingitinpreparingamealisagoodwayto59possiblewaterpollution,especiallyifthewaterhasbeen60foranhourormore.41.A.basketsB.windowsC.shelvesD.carts42.A.largeB.plasticC.coolD.cheap43.A.popularB.expensiveC.freshD.good44.A.natureB.trueC.faceD.health45.A.studyB.stickC.listD.print46.A.findB.addC.exploreD.mix47.A.mistakenB.misunderstoodC.misleadingD.misreading48.A.LawsB.NoticesC.ProductsD.Inventions49.A.nearbyB.hotC.undergroundD.overflowing50.A.withB.besidesC.beforeD.over51.A.considerB.trustC.doubtD.ensure52.A.suppliesB.pipesC.pollutionD.shortage53.A.producersB.riskC.elementsD.quality54.A.normallyB.regularlyC.repeatedlyD.instantly55.A.enoughB.excellentC.expensiveD.ideal56.A.collectedB.boiledC.changedD.tested57.A.useB.valueC.serviceD.importance58.A.runB.flowC.fillD.boil59.A.improveB.discoverC.limitD.solve60.A.shallowB.offC.slowD.on任务型阅读（共10小题；每小题1分，满分10分）请认真阅读下列短文，并根据所读内容在文章后表格中的空格里填入最恰当的单词。Everyyeartherearehundredsofearthquakesindifferentpartsoftheworld.InSept.1923,TokyoandYokohamawerebothdestroyedbyanearthquakeandthefiresthatfollowedit.Theyhadtobecompletelyrebuilt.OneofthemostseriousearthquakeswasinChina’sShanxiProvincein1556.Wemeasureanearthquake’sstrengthontheRichterscale.TheRichterscalewasintroducedin1935inSouthernCaliforniaintheUSA.Itmeasuresearthquakesonascaleofonetoten.Anyearthquakemeasuringfiveormoreisusuallyserious.Theearth’scrust(地壳)ismadeupoflayersofrockcalledplates.Astheseplatesmove,theysometimescrashagainsteachother,causingthecrusttoquake.IncitiessuchasTokyo,wheresmallquakeshappenquiteoften,manymodernbuildingsaredesignedtobeflexiblesowhentheearthmoves,theymovewithit.Earthquakescanalsobreakupgasoroilpipes.Thiscancausefirestobreakout,whichcandoasmuchdamageastheearthquakeitself.Anothereffectofearthquakesistsunamis(海啸).Thesearehugewavescreatedbyearthquakesbeneaththesea.Theycanbemanymetreshighandcausegreatdamagetocoastaltownsandcities.China,Japan,RussiaandtheUSAhavethehighestoccurrence(发生)ofearthquakesintheworld.Knowingabout71.__________Twoseriousearthquakesin72.__________Anearthquakeand73.__________firesdestroyedbothTokyoandYokohamainSept.1923.In1556,averyseriousearthquake74._________inChina’sShanxiThewayto75._________anearthquake’sstrengthPeoplecanmeasureanearthquake’sstrengthontheRichterscaleofonetoten,76._________in1935intheUSA.Ifanearthquakemeasuresfiveormore,it’susuallyserious.The77._______ofearthquakesAstheplates,whichformtheearth’s78._______,move,theysometimescrashagainsteachother,causingthecrusttoquake.Some79._____ofearthquakesIfearthquakesbreakupgasoroilpipes,80._______willhappen,whichcandoasmuchdamageastheearthquakeitself.Tsunamiisanothereffectofearthquakes.高三英语限时训练（一）完形填空41—45:CBADC46—50:BCACD51—55:CADBC56—60:DCACB任务型阅读:71.earthquakes72.history73.its74.happened75.measure76.introduced77.cause78.crust79.effects80.fires高三英语限时训练（二）完形填空（共20小题；每小题1分，满分20分）Afarmerhadsomepuppies(小狗)heneededtosell.Hepaintedasign36thepuppiesandsetaboutnailingittoapostonthe37ofhisyard.Ashewas38thelastnailintothepost,hefeltapullonhisclothes.Helookeddown39theeyesofalittleboy.“Mister,”hesaid,“Iwanttobuyoneofyourpuppies.”“40,”saidthefarmer,asherubbedthesweatoffthebackofhisneck,“thesepuppiescomefromfine41andcostmuchmoney.”Theboydroppedhisheadforamoment.Thenreaching42intohispocket,hepulledouta43ofcoinsandsaidtothefarmer.“I'vegotthirty-ninecents.Isthatenoughtotakealook?”“Sure,”saidthefarmer,andwiththathe44a45fromthedoghouseranDollyfollowedbyfourlittleballsoffur.Thelittleboy46hisfaceagainstthechainlinkfence.Hiseyesdancedwith47.Asthedogsmadetheir48tothefence,thelittleboynoticedsomethingelse.Anotherlittleballappeared,obviously49.Inasomewhat50mannerthelittlepuppybeganhobblingtowardtheothers,doingitsbesttocatchupwithothers.“Iwantthatone,”thelittleboysaid,pointingtoit.Thefarmer51downattheboy'ssideandsaid,“Son,youdon't.Hewillneverbeabletorunandplaywithyouliketheseotherdogs.”52thatthelittleboysteppedbackfromthefence,53down,andbeganrollinguponelegofhistrousers.Indoingsoheexposedasteelbrace(支持物)attachingitselftoa54madeshoe.Lookingup,hesaid,“Youseesir,Idon'truntoowellmyself,andhewillneedsomeonewhounderstands.”Yes,theworldisfullofpeoplewhoneedsomeonewho55.36.A.introducing B.showing C.advertising D.explaining37.A.back B.edge C.center D.top38.A.driving B.pushing C.entering D.taking39.A.to B.on C.for D.into40.A.Certainly B.Well C.Sorry D.Likely41.A.parents B.friends C.relatives D.customers42.A.deeply B.deep C.wide D.widely43.A.number B.piece C.handful D.deal44.A.wentout B.tookout C.letout D.foundout45.A.Away B.Far C.Out D.Into46.A.felt B.placed C.pushed D.pressed47.A.tears B.delight C.fear D.sorrow48.A.way B.direction C.path D.route49.A.whiter B.fatter C.thinner D.slower50.A.awkward B.forward C.smart D.interesting51.A.looked B.lay C.pointed D.knelt52.A.For B.In C.About D.With53.A.reached B.arrived C.lay D.put54.A.specially B.especially C.exactly D.naturally55.A.loves B.understands C.shares D.cares任务型阅读：请认真阅读下面短文，在表格中的空格里填上最恰当的单词(每空1个单词)Sincethebeginningofhumanevolution,menhavemigrated（迁移）acrosscontinentsinsearchoffood,shelter,safety,andcomfortableweather.Peoplestillmoveforthesereasons,butnewreasonsforhumanmigrationarearising,suchasjobrelocation(重新安置)andoverpopulation.Threemillionmigrantsaremovingfrompoorcountriestowealthieroneseachyear,andincreasingly,theirdestinationisaneighboringcountryindevelopingpartsoftheworld.Peoplearemovingwithinthedevelopingworldforthesamereasonsastheymigratetowealthiernations.Peoplefrompoorcountriesaregoingtolesspoorcountries,fleeingwarsandconflicts.Theyarealsorespondingtopopulationpressuresbecausesomecountriesaredenselypopulated,andtheyoftenhavehighpopulationgrowth.Thosepeopleneedtogosomewhereelse.Therearethreemainreasonswhypeoplemove.Thebasiccategoriesandpercentagesareasfollows,accordingtotheCurrentPopulationSurveys(CPS):Family-relatedreasonsaccountfor26.3%,includingchangesinmarital（婚姻的）status,establishingahouseholdandotherfamilyreasons;work-relatedreasons16.2%,includingjobtransfer,retirement,andotherjob-relatedreasons;housing-relatedreasons51.6%,includingnewandbetterhouses,betterneighborhood,cheaperhousingandotherhousingreasons;theremaining5.9%ofotherreasonsareattendingcollege,thechangeofclimateandhealthreasons.Americanshavebeenmigratingsouthandwestfordecadesinsearchofbetterjobopportunitiesandwarmerclimates.Theyhavealsobeenmovingtoplacesalittlefarfromcities,insearchofbiggeryardsandhouses,lowercrimeratesandbetterschools.In1950,nearlyafifthofthepopulationlivedinthenation’s20largestcities.In2006,itwasaboutoneinten.That’swhymanyAmericanpeoplesay,“BigCitiesShrinkasPeopleMoveSouth,West.”BetweenMarch2005andMarch2007,73.4millionAmericansmoved.Fifty-sixpercentofthesemoveswerewithinthesamecountry.Twentypercentwerebetweencountiesbutinthesamestate.Nineteenpercentweremovestoadifferentstate.Somefamiliesevenwentabroad.Title:Peopleonthe71Lead-inThroughouthuman72,peoplehavemigratedacrosscontinents.An73numberofpeoplefrompoorcountriesaremovingto______74countries,especiallyneighboringones.75_forpeople’smigrationAccordingtotheCPS,the76ofpeoplemovetootherplacesforreasons77tohousing.Americanshavelongbeenmovingsouthandwest,looking78abetterjobchance,awarmer79ConclusionNoweveryyearmoreandmorepeoplemovetootherplaces,whichseemstohavebecomeaglobal80.高三英语限时训练（二）完形填空36－40CBADB;41－45ABCCC;46－50DBADA;51-55DDAAB任务型阅读：71.move,72.history,73.increasing,74.richer/wealthier,75.Reasons,76.majority,77.related/linked,78.for,79.climate,80.tendency/phenomenon/trend高三英语课后限时训练（三）完形填空(共20小题；每小题1分，满分20分)TomJankowitzfinallygotintotheairportlounge.Hesatdownandopeneduphislaptopcomputer,keepingone36onthesmalltelevisionwhichshowedthedeparturetimesofallthe37fromtheairport.Tomwastiredandbored.ItwasChristmas,nearly.Tom38Christmas.HeonlyrememberedthatitwouldbeChristmastomorrow39therewereChristmasdecorationsallovertheairport.TomhadbeentoabusinessmeetinginNewYorkandhadtotakeaplanebackhome.Themeetinghadbeen40.Hehaddecidedtoclosealotofhiscompany’sofficesandalotofpeoplewere41abouthisdecision.Tomthoughtthathewouldrather42Christmasonhisowninahotelroomwithhiscomputer.Tomhardly43asthetelevisionscreenwiththedeparturetimesonitwentoff.Helookedupjust44toseeitbeforeallthelightsintheairportwentoff,too.Soon,45wastotally,completelyandutterlyblack.Theonlylightcamefromthetinylittlelightsonthewingsoftheaeroplanes,andthelight46hisownportablecomputerscreen.Soon,therewasan47,“Ladiesandgentlemen,we48toinformyouthatthereseemstohavebeenapowercut.Allflightsforthemomentare49.Thankyou.”AmansatdownnexttoTom.“Lookslikewe’renotgoinganywheretonight”hesaid.Tomdidn’treply,butnoddedin50.“Notgoinganywhere”,hethought.“I’mnotgoinganywhere.Nottonight,not51.TheonlyplacesIevergoareofficesofGlobalPowerInternational.”Tomwatchedthelightsgoing52onagainintheairportandheardthesoundofpeoplecheering.He53aswell,andsmiledatthemanwhowassittingnexttohim.Hefeltlikesomeonehadturneda54oninhimtoo.Hewaslookingforwardtobeinghome.“I’mgoing55”36.A.ear B.eye C.hand D.leg37.A.flights B.planes C.passengers D.pilots38.A.missed B.forgot C.suffered D.hated2,4,639.A.though B.unless C.because D.until2,4,640.A.long B.difficult C.boring D.successful41.A.unfair B.unfortunate C.unhappy D.unkind42.A.keep B.save C.spare D.spend43.A.noticed B.doubted C.moved D.stopped44.A.inorder B.intime C.inreturn D.incase45.A.nothing B.anything C.something D.everything46.A.on B.with C.from D.by47.A.advice B.announcement C.advertisement D.apology48.A.decide B.forgive C.regret D.begin49.A.delayed B.checked C.prepared D.cancelled50.A.agreement B.surprise C.anger D.excitement51.A.yet B.really C.only D.ever52.A.over B.back C.up D.straight53.A.heard B.watched C.celebrated D.cheered54.A.light B.radio C.heater D.heart55.A.nowhere B.everywhere C.anywhere D.somewhere任务型阅读请认真阅读下列短文，并根据所读内容在文章后表格的空格处里填人最恰当的单词。注意：每个空格填1个单词。Brazil’snextsuperstarRomRonaldoandRonaldinhotoKakaandRobinho,BrazilTheteenagestrikerscoredtheonlygoalofthegameonMarch20tohelpACMilanbeatTorino1-0.ThewinensuredMilancanstillmaintaintheirpushforaChampionsLeaguespotdespitetheabsenceofstarplaymakerKaka.PatomadehisstartinSerieAonlyinJanuaryandhasscoredsevengoalsforhisclubsofar.HealsohelpedBrazil’snationalfootballteamwinthe2007SouthAmericanYouthChampionship,whichqualifiedthecountryforthefootballcompetitionattheBeijingOlympicGames.Patoisgoodatcontrollingfootballandmovesintelligently.Butmostofall,heisquick.Lookingathimplay,itbecomesevidentwhymanypeoplehaveconnectedhimwithayoungRonaldo.YetPatoinsiststhatthepraisedoesnotputhimunderpressure.Instead,hewelcomesit.“IwashappytolistentopeoplesayingIwasagreatplayer.Itmakesmewanttodomybest.”Patostartedtoplayindoorfootballattheageofthree.Atonly11,hesignedwiththeBrazilianfootballclubInternacionalwherehestartedsharingahousewith83otherteenagers.Muchlikehim,theywantedtomakeanameforthemselvesintheclub’sseniorteam.Luckily,PatowastheonewhoquicklymadehiswaytotheseniorteamandlandedinACMilanattheendof2007.Wasiteasyforhimtosettledowninatotallydifferentculture?Patoinsiststhathehassettledinwithnoproblemsthankslargelytohiscompatriots(同胞)intheItalianleague.“ThesearetheplayersIplayedwithonPlaystationandwatchedontelevision,”headmitted.“MydreamofplayingwithmyidolRonaldohasfinallycometrue.”GettingtoknowAlexandrePatoNameAlexandrePato(71)________BraPlayingforACMilanHisfootball(72)_________Attheageof3Startedtoplay(73)________footballAtonly11(74)________withaBrazilianfootballclub,InternacionalAttheendof2007LandedinACMilanHisfootball(75)_________HescoredtheonlygoalofthegameonMarch20tohelpACMilan(76)________Torino1-0.Patohasalreadyscored(77)________goalsforhisclub.HealsohelpedBrazil’snationalfootballteamwinthe2007SouthAmericanYouth(78)__________.HisfootballskillsPatohasgood(79)______andmovesintelligently.Butaboveall,heisquick.Manypeoplehave(80)________himtoayoungRonaldo.高三英语课后限时训练（三）完形填空36-40BADCB41-45CDABD46-50CBCDA51-55DBDAD任务型阅读71.Homeland/Country72.history/experience/career73.indoor74.Signed75.achievements76.defeat/beat77.seven78.Championship79.control80.linked高三英语课后限时训练（四）完形填空(共20小题；每小题1分，满分20分)Manyofthetouristsonboardhadbegunbargainingwiththetradesmen,butIdecidednottobuyanything.Ihadnosoonergotoffthe36thanIwasstoppedbyamanwhowantedto37meadiamondring.Ihadno38ofbuyingone,butIcouldnotdenythefactthatIwas39bythesizeofthediamonds.Someofthemwereas40asmarbles(玻璃球).Themanwenttogreatlengthsto41thatthediamondswerereal.As42walkedpastashop,heheldadiamond43againstthewindowandmadeadeepimpressioninthe44.Ittookmeoverhalfanhourtogetridofhim.Thenextmanto45mewassellingexpensivepensandwatches.I46oneofthepensclosely.Itcertainlylooked47.Atthebaseofthegoldcap,thewords“madeintheUSA”hadbeenclearly48.Themansaidthatthepenwasworth￡50,butasaspecial49,hewouldletmehaveitfor￡30.I50myheadandheldupfivefingersindicatingthatIwaswillingtopay￡5.Gesturingwildly,themanactedasifhefoundmy51shocking,butheeventually52thepriceto￡10.Shruggingmyshoulders,Ibegantowalkaway.Amomentlater,heranaftermeand53thepenintomyhands.Thoughhekeptthrowinguphisarmsindespair,he54acceptedthe￡5Igavehim.Ifeltespeciallypleasedwithmywonderful55untilIgotbacktotheship.NomatterhowhardItried,itwasimpossibletofillthisbeautifulpenwithink！36.A.ship B.train C.plane D.bus37.A.show B.sell C.buy D.give38.A.money B.hobby C.experience D.intention39.A.ashamed B.impressed C.moved D.cheated40.A.colorful B.big C.heavy D.small41.A.prove B.explain C.instruct D.perform42.A.they B.he C.we D.people43.A.sharply B.quickly C.slowly D.forcefully44.A.assistant B.shop C.glass D.door45.A.approach B.call C.find D.look46.A.checked B.examined C.noticed D.watched47.A.expensive B.ordinary C.natural D.real48.A.marked B.signed C.found D.recognized49.A.feeling B.favour C.reason D.present50.A.shook B.nodded C.held D.touched51.A.decision B.answer C.offer D.solution52.A.reduced B.gave C.suggested D.had53.A.threw B.snatched C.brought D.forced54.A.angrily B.disappointedly C.readily D.clearly55.A.experience B.bargain C.advice D.balance任务型阅读（共10小题，每小题１分，满分10分）请认真阅读下列短文，并根据所读内容在文章后表格中的空格里填入最恰当的单词。注意：每空格只填一个单词。Haveyoueverbeeninameetingwhilesomeonewasmakingaspeechandrealizedsuddenlythatyourmindwasamillionmilesaway?Youprobablyfeltsorryandmadeupyourmindtopayattentionandeverhavebeentoldthatdaydreamingisawasteoftime.“Onthecontrary,”saysL.Giambra,anexpertinpsychology,“daydreamingisquitenecessary.Withoutit,themindcouldn’tgetdoneallthethinkingithastododuringanormalday.Youcan’tpossiblydoallyourthinkingwithaconsciousmind.Instead,yourunconsciousmindisworkingoutproblemsallthetime.Daydreamingthenmaybeonewaythattheconsciousandunconsciousstatesofmindhavesilentdialogues.”Earlyexpertsinpsychologypaidnoattentiontotheimportanceofdaydreamsorevenconsideredthemharmful.Atonetimedaydreamingwasthoughttobeacauseofsomementalillnesses.Theydidnothaveabetterunderstandingofdaydreamsuntilthelate1980s.EricKlinger,aprofessorofpsychology,isthewriterofthebookDaydreaming.Klingersays,“Weknownowthatdaydreamingisoneofthemainwaysthatweorganizeourlives,learnfromourexperiences,andplanforourfutures.Daydreamsreallyareawindowonthethingswefearandthethingswelongforinlife.”Daydreamsareusuallyverysimpleanddirect,quiteunlikesleepdreams,whichmaybehardtounderstand.It’seasiertogainadeepunderstandingofyourlifebypayingcloseattentiontoyourdaydreamsthanbytryingtoexamineyoursleepdreamscarefully.Daydreamshelpyourecognizethedifficultsituationsinyourlifeandfindoutapossiblewayofdealingwiththem.Daydreamscannotbepredicted;theymoveoffinunexpecteddirectionwhichmaybecreativeandfullofideas.Formanyfamousartistsandscientists,daydreamswereandareamainsourceofcreativeenergy.AboutdaydreamsOpinions1._________Features2._________A.3._________:onewaythatthe4._________andunconsciousstatesofmindhave5._________dialoguesorganizeourlivescannotbepredictedA.daydreams:7._________anddirectB.harmful:a8._______ofsomementalillnesseslearnfromour6._________moveoffinunexpected9.________B.10.________dreams:hardtounderstand高三英语课后限时训练（四）完形填空36-40ABDBB41-45ACDCA 46-50BDABA51-55CADCB任务型阅读1.Advantages 2.Differences 3.necessary 4.conscious 5.silent6.experiences 7.simple 8.cause 9.direction 10.sleep高三英语课后限时训练（五）完形填空（共20小题，每小题1分,满分20分）Whenwetalkaboutabadman,weliketocallhima“wolf”.Butisitreallytruethatthewolfstandsfordevilandugliness.Haveyoureadthebook“TheWolfTotem”byafamouswriterJiangRong,whichtellsthestoryoftherelationshipbetweenwolvesandhumanbeings?Haveyouever21thewolves'world?Ifyouhad,youwould22thewolves.Inthebook,wolvesareheroesonthelargegrassland.Theyknowmoreabout23thanhumans.Theycanattacklambswithoutdisturbingtheirmothers.Theyalsoknowhowto24fulluseoftheshapeoflandto25sheep.Ibelievethatifwolveswerehumans,theywouldbe26expertsgoodatfighting.Thewolfisakindofspecialcreaturethatcandeeplyunderstand27.Eachwolfservesitsgroupwithitsheartandsoul.A28wolfhaslittlepower,butapackofwolves29nothing.Allthewolvesobeytherules.30theyaredefeated,theyrunawaytogether.Itistheirteamwork31makeswolvespowerful.Thewolvesalsohavegreatself-respectandwon't32toanyone.Thewriter,whowrotethebook“TheWolfTotem”,33stoleaone-month-oldbabywolfandraiseditverycarefully.Tohis34,hefoundthelittlewolfstillwantedtogobackwith35wolves.Hebitthroughtheironchainthatlimitedhim.Thewolfwas36andhenevergavein,fighting37hisdeath.Thelittlewolfdiedasagloriousfighter.Iwasshockedbythiskindof38:wolvesareoneofthemostrespectedcreaturesonearth.Iwanteveryonetolookatwolvesina39way.Theyareourteachers.Theyshowushowtosurviveand40inthisnotsimpleanddangerousworld.Pleasehonorthewolves,pleasehonoralltheseheroesofnature!21.A.thoughtabout B.walkedinto C.talkedabout D.caredfor22.A.hunt B.admire C.draw D.watch23.A.space B.spot C.food D.survival24.A.get B.take C.have D.make25.A.fight B.avoid C.trap D.discover26.A.special B.imaginative C.outstanding D.creative27.A.operation B.teamwork C.lifestyle D.control28.A.single B.brave C.lonely D.fair29.A.fight B.struggle C.fear D.fail30.A.Asfor B.Asthough C.Evenso D.Evenif31.A.what B.he C.that D.one32.A.turnin B.givein C.takein D.breakin33.A.once B.just C.soon D.only34.A.satisfaction B.disappointment C.pleasure D.sorrow35.A.rest B.others C.another D.theother36.A.proud B.satisfied C.willing D.eager37.A.until B.although C.before D.unless38.A.selflessness B.self-confidence C.self-respectD.self-protection39.A.curious B.different C.strange D.humorous40.A.walk B.hand C.get D.succeed任务型阅读（共10小题，每小题１分，满分10分）请认真阅读下列短文，并根据所读内容在文章后表格中的空格里填入最恰当的单词。注意：每空格只填一个单词。Ifenvironmentaltrendscontinueonapositivetrack,somedaychildrenmayask,“Mommy,whatwaspollution?”Butbetweenthatdayandoursstandstheenvironmentalproblem:globalwarming.Fightinganartificialgreenhouseeffectisthegreatestofenvironmentalchallenges,becausethecurewillnotbepossibleunlessalmosteverynationontheEarthparticipates.Willglobalwarmingcauseharm?Somecomputermodelssuggesttheworldmightwarmby5degreesormoreduringthiscentury,whichmightbedangerous.Meltingpolaricecouldraisesealevels,whileglobalwarmingmightcausemoreintensestormsanddisrupttheweatherpatternsthatbringraintoagriculturalregions.Computermodelsarejustaguess,ofcourse,butwhenthefarmingareasthatwealldependuponforfoodrelyoncurrenttemperatures,rollingthedice(骰子)withtheclimatecannotbewise.YettodaytheUnitedStateshasnonationallawregulatinggreenhousegases.Therearemethodstoreduceglobalwarming.Forinstance,individualscanmakelifestylechanges.ReplaceanSUVwitharegularcar;anSUVgivesoff100tonsofgreenhousegasesoveritslifetime,whichisfarmorethanacardoes.Moderateyouruseofhomeheatingandairconditioning,mostofwhichispoweredbyfossilfuels,andupgradeappliancestoenergy-savingmodels.Besides,emissions(排放)tradingisagoodmeasure.In1990,risinglevelsofacidrainwereconsideredanemergencyproblem.Congresspassedanemissions-tradingprogram,whichallowedindustrialmanagerstobuyandsellpermitstoemitalimitedamountofpollutantsthatcauseacidrain.Theacid-raintradingprogramcreatedafinancialmotivationtoinventtechnologytoreduceacidrain;ifafactoryorpowerplantcutitsemissionsbelowthelimit,itcouldselltheextracreditsataprofit.Oncetherewasmoneytobemadebyreducingacidrain,humancreativitycameintoplay.Theresultswerespectacular.StagesofEnvironmentPresentFutureWearefacedwi