托福作文写作范文详解erio.docx

托福作文写作范文详解ReadingThelittleiceagewasaperiodofusuallycoldtemperatureinmanypartsoftheworldthatlastedfromabouttheyear1350until1900.Therewereunusuallyharshwinters,andglaciersgrewlargerinmanyareas.ScientistshavelongwonderedwhatcausedtheLittleIceAge.Severalpossiblecauseshavebeenproposed.First,thecoolingmayhavebeencausedbydisruptingofoceancurrents.BeforetheLittleIceAgeztherewasaperiodofunusuallywarmweatherduringwhichglaciersmelted.ThesemeltedglacierssentalargeamountofcoldfreshwaterintotheGulfStream,alargeoceancurrentthatstronglyaffectsEarth'sclimate.SomescientistsbelievethatthisfreshwaterwasenoughtotemporarilydisrupttheGulfStream.SuchadisruptioncouldhavecausedtheLittleIceAge.Second,volcaniceruptioncouldhavecausedtheLittleIceAge.Whenvolcanoeseruptztheysenddarkcloudsofdustandsulfurgasintotheatmosphere.Theseclouds,whichcanspreadovergreatareas,blocksomesunlightfromreachingEarth'ssurface.Thiscandecreasetheglobaltemperatures.ScientistsknowofseveralvolcaniceruptionsthattookplaceduringtheLittleIceAge.Third,Substantialdecreasesinhumanpopulationsmayhavecontributedindirectlytothecoolingoftheclimate.Foravarietyofreasons(disease,warfare,socialdisruption),thehumanpopulationjustbeforetheLittleIceAgeandduringtheearlypartofitwaslowerthanithadbeeninalongtime.Foresttreesstartedgrowingonfieldsthatwerenolongerusedforagriculture.Sincetreesabsorbcarbondioxide,agreenhousegasztheydecreasethegreenhouseeffectthatkeepsEarthwarm.Withmoreforesttreesabsorbingcarbondioxide,Earthbecamecooler.ListeningUnfortunately,theargumentsofthereadingpassagearealittleoutofdate.ScientistsnowhavenewinformationthatshowsthatnoneoftheideasthereadingpassagediscussescouldaccountfortheLittleIceAge.First,abouttheGulfStream.ScientistsnowknowthatdisruptingtheGulfStreamwouldcausecoolingonlyinEuropeandNorthAmerica,buttheLittleIceAgealsoaffectedtheSouthernhemisphere,inplaceslikeNewZealandandSouthAfricaforexample.SincethedisruptionoftheGulfStreamcannotexplainwhythesesouthernareasbecamecolder,itcannotexplaintheLittleIceAge.Second,thevolcanoestheory.Itzstruethatifvolcaniceruptionsputenoughdustintotheatmosphere,theresultcanbeacoolerclimate.Butlargeamountsofvolcanicdustintheatmospherewouldhavealsoproducedstrikingvisualeffectthatpeoplewouldhavenoticedatthetime.Forexample,dramaticallycolorfulsunsetsorsnowbeinggreyorbrowninsteadofwhite.ButtherearealmostnoreportsofanythinglikethatroutinelyhappeningduringtheLittleIceAge.Soitseemsthatthevolcaniceruptionsduringthatperiodweresimplynotstrongenoughtoreleasethelargeamountsofdustneededtolowerglobaltemperatures.Third,aboutforestsonfarmlandstoppingthewarminggreenhouseeffectbyremovingcarbondioxide.Therejustwasnotenoughtimeforthiseffecttowork.Thehumanpopulationgrewbacktopreviouslevelsfairlyquickly,whichmeantthatforestsweresoonbeingcutdownagaintoclearfieldsforthecropsneededtofeedthegrowingpopulation.Asaresult,weknowthattheforestsmentionedinthereadingpassagewerenottherelongenoughtocausethelong-termglobalcoolingoftheclimate.一、阅读听力要点概括ReadingPassagel>Thecoolingmayhavebeencausedbydisruptingofoceancurrents.2、Second,volcaniceruptioncouldhavecausedtheLittleIceAge.3、Third,Substantialdecreasesinhumanpopulationsmayhavecontributedindirectlytothecoolingoftheclimate.Lecture1、TheGulfStreamwouldcausecoolingdisruptingonlyinEuropeandNorthAmerica,buttheLittleIceAgealsoaffectedtheSouthernhemisphere.2、Largeamountsofvolcanicdustintheatmospherewouldhavealsoproducedstrikingvisualeffectsthatpeoplewouldhavenoticedatthetime.ButtherearealmostnoreportsofanythinglikethatroutinelyhappeningduringtheLittleIceAge.3、Therewasnotenoughtimeforforestsonfarmlandtostopthewarminggreenhouseeffectbyemovingcarbondioxide.二、范文逐段赏析Paragraph1Inthereadingpassage,theauthorclaimsthatthecauseoftheLittleIceAgewasduetothreemainreasons.Thelecturer,however,refutesthewriter'sopiniononebyonewithstrongarguments.此段功能首段是总领段，指出了文章与讲座存在不同观点，为接下来的论述做好了铺垫。此段结构此段是并列结构，提出了双方争论的焦点。Paragraph2Firstly,thepassagearguesthattheGulfStreamformedinthepreviouswarmperiodwasresponsiblefortheappearanceoftheunexpectedLittleIceAge.Yetzthespeakerarguesthattheso-calledGulfStreamonlycontributedtothecoolingweatherinNorthernhemispherewhileLittleIceAgetookplaceallovertheworld.ThuszglobalLittleIceAgecannotbeattributedtotheGulfStreaminsomepartsoftheplanetlikeNewZealandandSouthAfrica.此段功能此段提出阅读材料与演讲中的第一个矛盾点。阅读材料认为之前暖季出现的墨西哥湾洋流是导致意外小冰期出现的原因。然而演讲中反驳道，墨西哥湾洋流只可能导致北半球的冷气候，而小冰期事实上在全球范围内都有发生，因此在新西兰和南非等地的小冰期无从解释。此段结构此段是并列结构，分别论述。Paragraph3Next,accordingtothereadingmaterial,dustandsulfurgascausedbyvolcaniceruptionswouldblocksunlight,andthusresultedintheLittleIceAge.Thelecturer,however,holdsthatvolcaniceruptionsshouldhaveledtoothervisualphenomenathancoolingweather,likecolorfulsunsetsorgreysnow.Butunfortunatelynoneofthemwerereported.Ifthisistakenintoconsideration,volcaniceruptionsdonotseemstrongenoughtoreleasethelargeamountsofdustsneededtolowerglobaltemperatures.此段功能在此段中阅读材料指出另一个观点，即火山爆发引起的灰尘气体等遮住了太阳，进而导致了小冰期。而演讲中指出，如果火山爆发足够巨大，那么应该会有相关报道。因为历史上并没有此方面报道，则说明火山爆发没有那么大规模，也就不可能导致将整个地球温