托福作文写作范文详解ppo.docx

托福作文写作范文详解ReadingAfossilskeletonofadinosaurcalledSinosauropteryxzpreservedinvolcanicashzwasdiscoveredinLiaoningzChinazin1996.Interestingly,thefossilincludedapatternoffinelinessurroundingtheskeletalbones.SomepaleontologistsinterpretthelinesasevidencethatSinosauropteryxhadfeathers.However,criticshaveopposedtheideathatSinosauropteryxwasafeathereddinosaur,citingseveralreasons.First,thecriticspointsoutthatthefinelinesmaynotevenrepresentfunctionalstructuresofalivingdinosaur,butratherstructuresthatwereformedaftertheanimasdeath.Aftertheanimaldiedandwasburiedinvolcanicashzitsskinmayhavedecomposedintofibers.Theskinfibersthenbecamepreservedaslinesinthefossil;thelinesweremisinterpretedasevidenceoffeathers.Second,evenifthefinelinesareremainsofrealstructuresofaSinosauropteryxzscientistscannottellwithcertaintywhatpartofthedinosaur'sanatomythestructureswere.Manydinosaurshadfrillszornamentalfan-shapedstructuresgrowingoutofsomepartsoftheirbodies.Someofthecriticsarguthatthelinessurroundingtheskeletonaremuchmorelikelytobefossilizedremainsoffrillsthanremainsoffeathers.Athirdobjectionisbasedonthefactthattheusualfunctionsoffeathersaretohelpanimalsflyorregulatetheirinternaltemperature.However,thestructuresrepresentedbythelinesintheSinosauropteryxfossilweremostlylocatedalongthebackboneandthetailoftheanimal.Thiswouldhavemadethestructuresquiteuselessforflightandofverylimiteduseinthermoregulation.Thissuggeststhatthelinesdonotrepresentfeathers.ListeningNowlistentopartofalectureonthetopicyoujustreadabout.ProfessorTheevidencethatthelinesintheSinosauropteryxfossilrepresentfeathersisverystrong.Theargumentsofthecriticsareunconvincing.First,itisunlikelythatthelinesarearesultofthedecompositionofthedinosaur'sskinzbecausewedon'tseeanysuchdecompositioninthefossilsofotheranimalsburiedatthesamesite.Infactzthefossilsofmanyotheranimalsburiedatthesiteshowevidencethattheirfunctionalskinstructureshavebeenbeautifullypreservedinvolcanicash.Thewell-preservedconditionoftheotherfossilsmakesitlikelythattheSinosauropteryx,slinesarealsowell-preservedfunctionalstructures,possiblyfeathers,andthattheyarenotfiberscausedbydecomposition.Second,theideathatthelinesrepresentfrills.,well,thereisanimportantchemicaldifferencebetweenfeathersandfrills.FeatherscontainagreatdealofaproteincalledBeta-keratin.Frillszontheotherhand,donotcontainbeta-keratin.OurchemicalanalysessuggestthattheSinosauropteryxstructuresdidcontainbeta-keratin.Sothatindicatesthatthestructureswerefeathers,notfrills.Third,featherscanbeusedforotherfunctionsthanflightandthermoregulation.Thinkofabird,likepeacock,forexample.ThepeacockhasIongzcolorfulfeathersinitstail.Anditdisplaysitstailinordertoattractamate.That'sadistinctfunctionoffeatherscalledthedisplayfunction.Recently,wehavebeenabletodoanalysesontheSinosauropteryxstructuresthatshowusthatthestructureswerecolorful.Theywereorangeandwhite.Thefactthattheywerecolorfulstronglysupportstheideathattheywerefeathersthatthisdinosaurusefordisplay一、阅读听力要点概括PassageReading1. SomepaleontologistsinterpretthelinesasevidencethatSinosauropteryxhadfeathers.However,criticshaveopposedthisidea.2. First,thefinelinesmaynotevenrepresentfunctionalstructuresofalivingdinosaur,butratherstructuresthatwereformedaftertheanimasdeath.3. Second,thelinessurroundingtheskeletonaremuchmorelikelytobefossilizedremainsoffrills.4. AthirdobjectionisthatthestructuresrepresentedbythelinesintheSinosauropteryxfossilwouldhavemadethestructuresquiteuselessforflightandofverylimiteduseinthermoregulation.Lecture1. Thecritics'argumentsarenotsoconvincing.2. First,itisunlikelythatthelinesaretheresultofthedecompositionofthedinosaur'sskinzbecausewedonztseeanysuchdecompositioninthefossilsofotheranimalsburiedatthesamesite.3. SecondzchemicalanalysissuggeststhattheSinosauropteryxdonotcontainbeta-keratinthatfrillsdonotcontain,butfeathersdo.4. 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。Paragraph2Tostartwithzaccordingtothereading,thoselinesmayderivefromdecompositionofadeaddinosaur'sskininsteadofbeingpartofalivingone.Thelecturerdoesnotbelievethispointforthereasonthatotheranimals'fossilsthatwereburiedatthesamesitehavenotshownsuchkindofdecomposition;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。Paragraph3Movingonzthereadingproposesthatthelinesmaybefrillsratherthanremainsoffeathers.Thelisteningarguesthisisnottrue.Shefurt