托福作文写作范文详解ppo.docx

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1、托福作文写作范文详解ReadingAfossilskeletonofadinosaurcalledSinosauropteryxzpreservedinvolcanicashzwasdiscoveredinLiaoningzChinazin1996.Interestingly,thefossilincludedapatternoffinelinessurroundingtheskeletalbones.SomepaleontologistsinterpretthelinesasevidencethatSinosauropteryxhadfeathers.However,criticshaveo

2、pposedtheideathatSinosauropteryxwasafeathereddinosaur,citingseveralreasons.First,thecriticspointsoutthatthefinelinesmaynotevenrepresentfunctionalstructuresofalivingdinosaur,butratherstructuresthatwereformedaftertheanimasdeath.Aftertheanimaldiedandwasburiedinvolcanicashzitsskinmayhavedecomposedintofi

3、bers.Theskinfibersthenbecamepreservedaslinesinthefossil;thelinesweremisinterpretedasevidenceoffeathers.Second,evenifthefinelinesareremainsofrealstructuresofaSinosauropteryxzscientistscannottellwithcertaintywhatpartofthedinosaursanatomythestructureswere.Manydinosaurshadfrillszornamentalfan-shapedstru

4、cturesgrowingoutofsomepartsoftheirbodies.Someofthecriticsarguthatthelinessurroundingtheskeletonaremuchmorelikelytobefossilizedremainsoffrillsthanremainsoffeathers.Athirdobjectionisbasedonthefactthattheusualfunctionsoffeathersaretohelpanimalsflyorregulatetheirinternaltemperature.However,thestructures

5、representedbythelinesintheSinosauropteryxfossilweremostlylocatedalongthebackboneandthetailoftheanimal.Thiswouldhavemadethestructuresquiteuselessforflightandofverylimiteduseinthermoregulation.Thissuggeststhatthelinesdonotrepresentfeathers.ListeningNowlistentopartofalectureonthetopicyoujustreadabout.P

6、rofessorTheevidencethatthelinesintheSinosauropteryxfossilrepresentfeathersisverystrong.Theargumentsofthecriticsareunconvincing.First,itisunlikelythatthelinesarearesultofthedecompositionofthedinosaursskinzbecausewedontseeanysuchdecompositioninthefossilsofotheranimalsburiedatthesamesite.Infactzthefoss

7、ilsofmanyotheranimalsburiedatthesiteshowevidencethattheirfunctionalskinstructureshavebeenbeautifullypreservedinvolcanicash.Thewell-preservedconditionoftheotherfossilsmakesitlikelythattheSinosauropteryx,slinesarealsowell-preservedfunctionalstructures,possiblyfeathers,andthattheyarenotfiberscausedbyde

8、composition.Second,theideathatthelinesrepresentfrills.,well,thereisanimportantchemicaldifferencebetweenfeathersandfrills.FeatherscontainagreatdealofaproteincalledBeta-keratin.Frillszontheotherhand,donotcontainbeta-keratin.OurchemicalanalysessuggestthattheSinosauropteryxstructuresdidcontainbeta-kerat

9、in.Sothatindicatesthatthestructureswerefeathers,notfrills.Third,featherscanbeusedforotherfunctionsthanflightandthermoregulation.Thinkofabird,likepeacock,forexample.ThepeacockhasIongzcolorfulfeathersinitstail.Anditdisplaysitstailinordertoattractamate.Thatsadistinctfunctionoffeatherscalledthedisplayfu

10、nction.Recently,wehavebeenabletodoanalysesontheSinosauropteryxstructuresthatshowusthatthestructureswerecolorful.Theywereorangeandwhite.Thefactthattheywerecolorfulstronglysupportstheideathattheywerefeathersthatthisdinosaurusefordisplay一、阅读听力要点概括PassageReading1. Somepaleontologistsinterpretthelinesase

11、videncethatSinosauropteryxhadfeathers.However,criticshaveopposedthisidea.2. First,thefinelinesmaynotevenrepresentfunctionalstructuresofalivingdinosaur,butratherstructuresthatwereformedaftertheanimasdeath.3. Second,thelinessurroundingtheskeletonaremuchmorelikelytobefossilizedremainsoffrills.4. Athird

12、objectionisthatthestructuresrepresentedbythelinesintheSinosauropteryxfossilwouldhavemadethestructuresquiteuselessforflightandofverylimiteduseinthermoregulation.Lecture1. Thecriticsargumentsarenotsoconvincing.2. First,itisunlikelythatthelinesaretheresultofthedecompositionofthedinosaursskinzbecausewed

13、onztseeanysuchdecompositioninthefossilsofotheranimalsburiedatthesamesite.3. SecondzchemicalanalysissuggeststhattheSinosauropteryxdonotcontainbeta-keratinthatfrillsdonotcontain,butfeathersdo.4. Feathershaveotherfunctions,likedisplayfunction.二、范文逐段赏析Paragraph1Thereadingpassagerefutestheideathattheline

14、sintheSinosauropteryxfossilindicatedafeathereddinosaurbydemonstratingseveralcounterarguments.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

15、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,thoselinesmayderivefromdecompositionofadeaddinosaursskininsteadofbeingpartofalivingone.Thelecturerdoesnotbelievethispointforthereasonthatotheranimalsfossilsthatwereburiedatthesamesitehavenotshownsuchkindofdecomposition;instead,

16、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