托福作文写作范文详解ppo

托福作文写作范文详解ReadingAfossilskeletonofadinosaurcalledSinosauropteryx,preservedinvolcanicash,wasdiscoveredinLiaoning,China,in1996.Interestingly,thefossilincludedapatternoffinelinessurroundingtheskeletalbones.SomepaleontologistsinterpretthelinesasevidencethatSinosauropteryxhadfeathers.However,criticshaveopposedtheideathatSinosauropteryxwasafeathereddinosaur,citingseveralreasons.First,thecriticspointsoutthatthefinelinesmaynotevenrepresentfunctionalstructuresofalivingdinosaur,butratherstructuresthatwereformedaftertheanimaTsdeath.Aftertheanimaldiedandwasburiedinvolcanicash,itsskinmayhavedecomposedintofibers.Theskinfibersthenbecamepreservedaslinesinthefossil;thelinesweremisinterpretedasevidenceoffeathers.Second,evenifthefinelinesareremainsofrealstructuresofaSinosauropteryx,scientistscannottellwithcertaintywhatpartofthedinosaur'sanatomythestructureswere.Manydinosaurshadfrills,ornamentalfan-shapedstructuresgrowingoutofsomepartsoftheirbodies.Someofthecriticsarguthatthelinessurroundingtheskeletonaremuchmorelikelytobefossilizedremainsoffrillsthanremainsoffeathers.Athirdobjectionisbasedonthefactthattheusualfunctionsoffeathersaretohelpanimalsflyorregulatetheirinternaltemperature.However,thestructuresrepresentedbythelinesintheSinosauropteryxfossilweremostlylocatedalongthebackboneandthetailoftheanimal.Thiswouldhavemadethestructuresquiteuselessforflightandofverylimiteduseinthermoregulation.Thissuggeststhatthelinesdonotrepresentfeathers.ListeningNowlistentopartofalectureonthetopicyoujustreadabout.ProfessorTheevidencethatthelinesintheSinosauropteryxfossilrepresentfeathersisverystrong.Theargumentsofthecriticsareunconvincing.First,itisunlikelythatthelinesarearesultofthedecompositionofthedinosaur'sskin,becausewedon'tseeanysuchdecompositioninthefossilsofotheranimalsburiedatthesamesite.Infact,thefossilsofmanyotheranimalsburiedatthesiteshowevidencethattheirfunctionalskinstructureshavebeenbeautifullypreservedinvolcanicash.Thewell-preservedconditionoftheotherfossilsmakesitlikelythattheSinosauropteryx^linesarealsowell-preservedfunctionalstructures,possiblyfeathers,andthattheyarenotfiberscausedbydecomposition.Second,theideathatthelinesrepresentfrills..,well,thereisanimportantchemicaldifferencebetweenfeathersandfrills.FeatherscontainagreatdealofaproteincalledBeta-keratin.Frills,ontheotherhand,donotcontainbeta-keratin.OurchemicalanalysessuggestthattheSinosauropteryxstructuresdidcontainbeta-keratin.Sothatindicatesthatthestructureswerefeathers,notfrills.Third,featherscanbeusedforotherfunctionsthanflightandthermoregulation.Thinkofabird,likepeacock,forexample.Thepeacockhaslong,colorfulfeathersinitstail.Anditdisplaysitstailinordertoattractamate.Thafsadistinctfunctionoffeatherscalledthedisplayfunction.Recently,wehavebeenabletodoanalysesontheSinosauropteryxstructuresthatshowusthatthestructureswerecolorful.Theywereorangeandwhite.Thefactthattheywerecolorfulstronglysupportstheideathattheywerefeathersthatthisdinosaurusefordisplay一、阅读听力要点概括PassageReadingSomepaleontologistsinterpretthelinesasevidencethatSinosauropteryxhadfeathers.However,criticshaveopposedthisidea.First,thefinelinesmaynotevenrepresentfunctionalstructuresofalivingdinosaur,butratherstructuresthatwereformedaftertheanimaTsdeath.Second,thelinessurroundingtheskeletonaremuchmorelikelytobefossilizedremainsoffrills.AthirdobjectionisthatthestructuresrepresentedbythelinesintheSinosauropteryxfossilwouldhavemadethestructuresquiteuselessforflightandofverylimiteduseinthermoregulation.LectureThecritics'argumentsarenotsoconvincing.First,itisunlikelythatthelinesaretheresultofthedecompositionofthedinosaur'sskinzbecausewedon'tseeanysuchdecompositioninthefossilsofotheranimalsburiedatthesamesite.Second,chemicalanalysissuggeststhattheSinosauropteryxdonotcontainbeta-keratinthatfrillsdonotcontain,butfeathersdo.Feathershaveotherfunctions,likedisplayfunction.二、范文逐段赏析Paragraph1ThereadingpassagerefutestheideathatthelinesintheSinosauropteryxfossilindicatedafeathereddinosaurbydemonstratingseveralcounterarguments.Thelecturer,however,isstronglyconvincedthatlinescouldrepresentfeathersthroughaddressingthequestionsadvancedbythereading.此段功能文章首段概括介绍了阅读中的观点，即认为化石中的线条不能显示这是一只有羽毛的恐龙。而演讲者则认为这些线条可以显示是恐龙的羽毛,指出双方的矛盾点，为下文论述做好铺垫。此段结构此段为并列结构，分别陈述了文章和演讲中的两方不同观点。Paragraph2Tostartwith,accordingtothereading,thoselinesmayderivefromdecompositionofadeaddinosaur'sskininsteadofbeingpartofalivingone.Thelecturerdoesnotbelievethispointforthereasonthatotheranimals1fossilsthatwereburiedatthesamesitehavenotshownsuchkindofdecomposition;instead,theirfunctionalskinstructureshavebeenperfectlypreservedinthevolcanicash.Therefore,theselinesarelikelytobewell-preservedfeathersinsteadoffibers.此段功能指出文章第一个观点，即认为这些线条是死亡恐龙的皮肤分解腐烂所致,而不是在一只活恐龙身上的一部分。但是演讲者反驳道，这一地区附近的化石上都没有这种腐烂现象，而且被火山灰保存得很好。由此可以证明这些线条就是恐龙的羽毛。此段结构此段并列结构，指出文章第一个观点，并提出了演讲者的反驳证据。Paragraph3Movingon,thereadingproposesthatthelinesmaybefrillsratherthanremainsoffeathers.Thelisteningarguesthisisnottrue.Shefurtherexplainsthatthereisanapparentchemicaldifferencebetweenfeathersandfrills.Featherscontainaproteincalledbeta-keratinwhilefrillsdonot.ThechemicalanalysissuggestedthatSinosauropteryx^structurescontaintheproteinbeta-keratin.此段功能指出文章第二个观点，即这些线条可能是褶皱而非恐龙的羽毛。演讲者进一步解释并反驳了这一点，褶皱和羽毛化学成分不一样，而化学分析显示，化石中包含有羽毛中才有的化学成分，以此来证明这些线条是恐龙羽毛。此段结构此段并列结构，指出文章第二个观点，并提出了演讲者的反驳证据。Paragraph4Lastbutnotleast,thereadingputsemphasisonsuchafactthatlinesaroundthebackboneandthetailoftheSinosauropteryxcannotplaytheroleofhelpingitflyorregulatingitsbodytemperaturebutcommonfeathershavethesefunctions.Thelecturer,bycontrastsme