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1、托福作文写作范文详解ReadingEndothermsareanimalssuchasmodernbirdsandmammalsthatkeeptheirbodytemperaturesconstant.Forinstance,humansareendothermsandmaintainaninternaltemperatureof37oCznomatterwhethertheenvironmentiswarmorcold.Becausedinosaurswerereptiles,andmodernreptilesarenotendothermszitwaslongassumedthatdin
2、osaurswerenotendotherms.However,dinosaursdifferinmanywaysfrommodemreptiles,andthereisnowconsiderableevidencethatdinosaurswerezinfactzendotherms.PolardinosaursOnereasonforbelievingthatdinosaurswereendothermsisthatdinosaurfossilshavebeendiscoveredinpolarregions.Onlyanimalsthatcanmaintainatemperaturewe
3、llabovethatofthesurroundingenvironmentcouldbeactiveinsuchcoldclimates.LegpositionandmovementThereisaconnectionbetweenendothermyandthepositionandmovementofthelegs.Thephysiologyofendothermyallowssustainedphysicalactivity,suchasrunning.Butrunningisefficientonlyifananimalslegsarepositionedunderneathitsb
4、ody,notatthebodyssidezastheyareforcrocodilesandmanylizards.Thelegsofallmodernendothermsareunderneaththebody,andsowerethelegsofdinosaurs.Thisstronglysuggeststhatdinosaurswereendotherms.HaversiancanalsThereisalsoaconnectionbetweenendothermyandbonestructure.Thebonesofendothermsusuallyincludestructuresc
5、alledHaversiancanals.Thesecanalshousenervesandbloodvesselsthatallowthelivinganimaltogrowquicklyzandrapidbodygrowthisinfactacharacteristicofendothermy.ThepresenceofHaversiancanalsinboneisastrongindicatorthattheanimalisanendotherm,andfossilizedbonesofdinosaursareusuallydensewithHaversiancanals.Listeni
6、ngProfessor:Manyscientistshaveproblemswiththeargumentsyoureadinthepassage.Theydontthinkthoseargumentsprovethatdinosaurswereendotherms.Takethepolardinosaurargument.Whendinosaurslived,eventhepolarregions,wheredinosaurfossilshavebeenfound,weremuchwarmerthantoday,warmenoughduringpartoftheyearforanimalst
7、hatwerenotendothermstolive.Andduringthemonthswhenthepolarregionswerecoldztheso-calledpolardinosaurscouldhavemigratedtowarmerareasorhibernatedlikemanymodernreptilesdo.Sothepresenceofdinosaurfossilsinpolarregionsdoesntprovethedinosaurswereendotherms.Wellzwhataboutthefactthatdinosaurshavetheirlegsplace
8、dundertheirbodies,notouttothesidelikecrocodiles.Thatdoesntnecessarilymeandinosaurswerehigh-energyendothermsbuiltforrunning.Thereisanotherexplanationforhavinglegsunderthebody.Thisbodystructuresupportsmoreweightsowiththelegsundertheirbodies,dinosaurscangrowtoaverylargesize.Beinglargehadadvantagesfordi
9、nosaurs,sowedontneedtheideaofendothermyandrunningtoexplainwhydinosaursevolvedtohavetheirlegsundertheirbodies.Okzsohowaboutbonestructure?ManydinosaurbonesdohaveHaversiancanals,thatstrue.Thedinosaurbonesalsohavegrowthrings.Growthringsarethickeningofthebonethatindicatesperiodsoftimewhenthedinosaurswere
10、ntrapidlygrowing.Thesegrowthringsareevidencethatdinosaursstoppedgrowingorgrewmoreslowlyduringcoolerperiods.Thispatternofperiodicgrowth,youknowzrapidgrowthfollowedbynogrowthorslowgrowth,andthenrapidgrowthagainzischaracteristicofanimalsthatarenotendotherms.Animalsthatmaintainaconstantbodytemperatureye
11、ar-roundastrueendothermsdogrowrapidlyevenwhentheenvironmentbecomescool.阅读听力要点概括ReadingPassageMainpoints:Evidencethatdinosaurswereendotherms.Subpoint1:Polardinosaursfound.Subpoint2:Legpositionsuggestsendotherms.Subpoint3:Bonestructureindicatesendothermy.LectureAttitude:Arguments.(Can,tproveendotherms
12、.)SubPoint1:Polarregionswerewarmer.(Migrateorhibernate.)SubPoint2:Legsjustforsupportmoreweight.SubPoint3:Growthrings.（Periodicgrowth.）范文逐段赏析Paragraph1Theprofessoractuallycontradictsthestatementsmadeinthereadingpassage.Sheisoftheviewthatdinosaurswerenotendotherms,orthattheywerenotabletokeeptheirbodyt
13、emperaturesataconstantrate.此段功能：（Listeningpassage后文提到用L代替）（Readingpassage后文用R代替）以L为主，作者开头段写出L反对R做出的观点。她认为恐龙不是暖血动物，或者不能把他们的体温维持恒定。此段结构：作者在开头段立刻表面了逻辑，随后总结了L的观点，准备开始辩论。Paragraph2Theprofessordisputestheissueofdinosaursbeingendotherms.Basedonthelimitedavailabilityoffossilsfromthepolarregions,sheassertsth
14、attheseregionswerenotascoldastheyaretoday,andcouldsustaindinosaurlifeduringwarmerseasons.Duringharshwintersshebelievesthatthereisapossibilitythatthedinosaursactuallymigratedtowarmerregions.此段功能：以L的观点开头，作者说L不认为恐龙是暖血动物，因为当地的极地气候没有现在这么冷，在温暖的时候也许可以让恐龙存活。在冬季的时候恐龙可以迁移到更温暖的地方去。此段结构：此段为总分结构，在第一个极地问题的讨论上，L给了
15、一系列证据支撑她的论点。Paragraph3Theissueoflegpositionandmovementbeingusedasareasontoclassifythedinosaursasendothermsdoesnotsatisfytheprofessoreither.Shesaysthatdinosaurshadlegsundertheirbodiestosupporttheirmassiveweights,andnottoprovideitwithabodystructurelikeotherendothermiccreatures,andonemoresuitedtorunnin
16、g.此段功能：作者继续说L认为大腿位置也不能证明恐龙是暖血动物。L解释恐龙的大腿在1区干下面主要是用于支撑体重或者跑步，不是像其他的暖血动物一样。此段结构：总分结构。作者带出L观点之后详细解释了L的证据。Paragraph4Theprofessoracknowledgesthepresenceofhaversiancanalsbutalsopointsoutthatthatthefossilsshowthepresenceofgrowthrings.Theseringsareduetothethickeningofadevelopingbone.Thethickeningindicatesth
17、atthedinosaurswerenztactuallygrowingcontinuouslybutwereexperiencingperiodsofbothrapidgrowthandnogrowthinsuccession.Shesaysthistypeofbonegrowthischaracteristicofnon-endothermicanimals.此段功能：讨论第三个分论点,作者写明L承认harversiancanals但是同时这些化石有生长年轮。生长年龄是因为恐龙生长期间的快慢差异导致的，这种现象是冷血动物特有的。此段结构：总分结构。第一句总结L观点。随后用新的例子打破R原来
18、的理论。Paragraph5Thusritcanbeinferredthattheprofessorchallengesthepassagebygivingreasonssupportingherpositionthatthedinosaurisnotanendotherm.此段功能：做最终总结，L给出了许多原因支持恐龙不是暖血动物此段结构：一句话作为收尾，呼应首段，L达到了证明效果。范文全篇总评1.逻辑结构全文遵从总分结构，开头段做出总结，展望论点，表面逻辑。随后三段依照3个分论点依次展开。在分论点的论证中，作者阐明了L的态度，补充新的证据，达到了一一驳倒R的效果。最后一段总结辩论效果达成。2、语言表达文章语言清晰，难度主要来自专业词，但是除了专业词汇并没有启用太多生词和长难句，其中可以借鉴的词句有：1. Theprofessordisputestheissueof.教授反对了.的观点2. Acknowledge:承认recognizecofessWeacknowledgetheneedofrevolution.
