托福作文写作范文详解ioxid.docx

托福作文写作范文详解ReadingEthanolfuelmadefromplantssuchascornandsugarcanezhasbeenadvocatedbysomepeopleasanalternativetogasolineintheUnitedStates.However,manycriticsarguethatethanolisnotagoodreplacementforgasolineforseveralreasons.First,theincreaseduseofethanolfuelwouldnothelptosolveoneofthebiggestenvironmentalproblemscausedbygasolineuse:globalwarming.Likegasoline,ethanolreleasescarbondioxideintotheatmospherewhenitisburnedforfuelandcarbondioxideisgreenhousegas:ithelpstrapheatintheatmosphere.Thus,ethanoloffersnoenvironmentaladvantageovergasoline.Second,theproductionofsignificantamountsofethanolwoulddramaticallyreducetheamountofplantsavailableforusesotherfuel.Forexample,muchofthecornnowgrownintheUnitedStatesisusedtofeedfarmanimalssuchascowsandchickens.Itisestimatedthatifethanolwereusedtosatisfyjust10percentofthefuelneedsintheUnitedStates,morethan60percentofthecorncurrentlygrownintheunitedstatedwouldhavetobeusedtoproduceethanol.Ifmostofthecornwereusedtoproduceethanolzasubstantialsourceoffoodforanimalswoulddisappear.Third,ethanolfuelwillneverbeabletocompetewithgasolineonprice.Althoughthepricesofethanolandgasolinefortheconsumerarecurrentlyaboutthesame,thisisonlybecauseofthehelpintheformoftaxsubsidiesgiventoethanolproducersbytheUnitedStatesgovernment.ThesetaxsubsidieshavecosttheUnitedStatesgovernmentover$11billioninthepast30years.IftheUnitedStatesgovernmentweretostophelpingproducersinthiswayzthepriceofethanolwouldincreasegreatly.ListeningEthanolactuallyisagoodalternativetogasoline,althoughyoujustreadthreereasonswhyitsnotagoodalternative,notoneofthesethreereasonsisconvincing.First,theincreaseduseofEthanolfuelwillnotaddtoglobalwarming.It,struethat,whenEthanolisburned,itreleasescarbondioxideintotheatmosphere,butasyouread,Ethanolisoftenmadefromplantssuchascorn.Well,theprocessofgrowingtheplantscounteractsthisreleaseofcarbondioxide.Letmeexplain.Everygrowingplantabsorbscarbondioxidefromtheairaspartofitsnutrition.SogrowingplantsforEthanolproductionactuallyremovescarbondioxidefromtheatmosphere.Second,largescaleproductionofEthanoldoesn,thavetoreducethesourcesoffoodforanimals.That,sbecausewecanproduceEthanolusingcellulose,celluloseisthemaincomponentofplants,cellwalls,andyou,llfindmostcelluloseinthosepartsofplantsthatarenoteatenbyanimals.SozsincewecanproduceEthanolfromtheplantpartsthataren,teaten,theamountofanimalfeedthatisavailablewillnotbereduced.Third,inthefuture,Ethanolwillbeabletocompetewithgasolineintermsofprice.ItstruethatgovernmentsubsidiesmakeEthanolcheaperthanitwouldnormallybe,butthissupportwon,talwaysbeneeded.OnceenoughpeoplestartbuyingEthanoLEthanolproducerswillincreasetheirproductionofEthanol.Generally,increasedproductionofproductsleadstoadropinitsprice.SothepriceofEthanolwillgodownasmoreofitbecomesavailable.Studiesshowthat,ifEthanolproductioncouldbethreetimesgreaterthanitisnowzthecostofproducingaunitofEthanolwilldropbyfortypercent一、阅读听力要点概括ReadingPassageMainpoints:ManyCriticsthinkethanolisnotagoodreplacementforgasoline.Subpoint1:EthanolemitsCO2whenitburnsandhasnoadvantagetoenvironment.Subpoint2:Productionofethanolcutsenergysupplytofood.Subpoint3:Ethanolpricewouldincreaseifgovernmentstopssubsidies.LectureAttitude:Notconvincing.SubPoint1:GrowingplantsabsorbsCO2soitremovesCO2fromatmosphere.SubPoint2:Ethanolisproduceusingpartsthataren,teaten.(Cellulose,mainofplants)SubPoint3:Ethanolcancompetewithgasinpriceinthefuture.(Increaseleadsdropinprice.)二、范文逐段赏析Paragraph1Thelecturerrefutesalltheevidenceinthereadingpassage,whichevidenceseemstoaffirmthereareexistingshortagesofethanol.Healsoholdsthatethanolisquitelikelyagoodreplacementofgasolineasafuturefuel.此段功能：（Listeningpassage后文提到用L代替）（Readingpassage后文用R代替）以L为根本，L觉得R的证据和观点都不可信，作者用了一个同义词refute（驳倒）,L驳倒了R的所有证据，觉得酒精是一个非常好的汽油代替品。此段结构：首段第一句话以L出发，L反对R的所有并复述R的观点。第二句复述L的观点，使读者知道L准备要反驳的点。Paragraph2First,theapplicationofethanolwillnotcreateasmuchheatastheuseofgasoline.Althoughtheburningofethanolalsogeneratescarbondioxide,itwillnotsignificantlyaddtotheseverityofglobalwarming.Sincetheproductionofethanolrequirestheplantingandharvestingofcorn,whichgrowthinturnrequirescarbondioxideasnutrition,theheightenedamountofunwantedgaswillbeoffsettherewith.Thisisthesituationforwhichthereadingdoesn'taccount.此段功能：引出第一个分论点，说大面积应用酒精并不会造成太多温室效应。因为酒精的种植过程会吸收很多二氧化碳。R中没提到这个吸收过程，L就攻击了这个点。此段结构：此段为总分结构，先列举L的观点，酒精不会产生那么多温室气体。然后就开始写L的证据，最后告诉读者，刚才举的证据恰好是R没想到的，R证据不足。Paragraph3Second,theproductionofethanoldoesn'treducethefoodsupplyforfarmanimals.Becauseethanolcanbemadeoutofanypartoftheplantcellwalls,whichcontaincellulose,thecostofusingtheplants'usefulpartscanbeavoided.Thisadvantagerenderstheworryofthereadingtotallyunnecessary.此段功能:引出第二个分论点，酒精制造是不会减少家禽的食物供给。因为酒精是使用不可作为食料的包含纤维素的植物细胞做的。R中提到的忧虑是毫无必要的。此段结构：此段为总分结构。先确立L的观点（不会减少食物供给），再给解释，最后说这个优势显得R的忧虑无必要，从而达到了驳到R的地步。Paragraph4Finally,thepriceofethanolwillbelargelyreducedifthescaleofmanufactureincreases.Accordingtostatistics,ifthemanufacturescale,followingheavierdemandofconsumers,canbeenlargedbythr