托福寫作沖刺王2web網(wǎng)智課課網(wǎng)

2121綜合寫作之高分要點(diǎn)—不拿白不拿的15 22Thereadingpassageproposesthreehypothesestoex inthesteadydeclineinpopulationsoftheyellowcedar.Unfortuna y,thelecturerarguesthatitisstillunknownthatwhatisthecausetothedeclineandnoneofthesethreehypothesesareadequateenough.First,thereadingpassagesuggeststhattheyellowcedardeclinemaybecausedbyinsectparasites,especiallybythecadarbarkbeetle.However,thespeakerrebutsthatactuallycedartreesaremoreresistenttopeststhanothertreessothathealthycadartreesareunlikelytobeattackedbyinsect.Itisonlysickcadartreesthatareattackedbybeetlelarvae,causingthedeclineinpopulationsofcadartrees.Inthiscase,cedartrees'ownhealthisthekeypointtosurvivalofcadartrees,ratherthanthethreatofbeetles.Second,accordingtothepassage,cedartreesdeclineattributesthedecreaseofbrownbears.Ontheotherhand,thelecturerstatesthatbearsdon'texertoverallinfluenceonpopulationsofcedartreesbygivinganexample.Insomeislands,therearenobearslivingbutpopulationsofcedartreesstillgodown,whichprovesthatbrownbearshavelittletodowithpopulationsofcedartrees.Third,thereadingpassagearguesthatgradualchangesofclimatemaybetoblame.Incontrast,thelecturerpointsoutthatthepassageforgetstotakefrostintoaccount,whichisalsoanimportantfactor.Moretreesdieinlowerelevationwhereitiswarmthaninhighelevationwhereitiscold.Asaresult,itcanbeconcludedthatthoughclimatechangemakescedartreesemoresensitive,itisnotthefundamentalcauseofcedartreesdecline.22綜合寫作之范文模仿—TPO3TherearethreeargumentsagainstthefactthatthefinelinessurroundingtheskeletonbonesofSinosauropteryxarefeathers.However,thelecturerthinksnoneofthemareconvincing.First,thepassageholdsthatthefinelinesarejustskinfibers posedfromadeaddinosaur,andthelinesdonotrepresentfunctionalstructuresofalivingdinosaur.However,thelecturerclaimsthatthefinelinesarenotskinfibersbecausethereisnosuch positionfoundinotheranimal’sfossilsatthesamesite.What’smore,thebeautifully functionalskinstructureswerediscoveredinotheranimal’sfossilsatthesamesite.ThatprobablymeanstheSinosauropteryx’slinesmayalsobefunctionalstructurelikefeathers.22綜合寫作之范文模仿—TPO3Thelectureralsochallengesthesecondargumentthatthelinesaroundtheskeletonarefossilizedremainsoffrillsratherthanremainsoffeathers.Accordingtothelecturer,featherscontainagreatamountofBeat-keratin,atypeofprotein,whichfrillsdonothave.AndsinceBeat-keratincanbefoundinSinosauropteryxstructures,thestructurescanonlybefeathers,butnotfrills.Finally,thepassageassertsthatthestructurerepresentedbylinesdoesnothavefeathers’practicalfunctionslikeflightandthermoregulation,becausethelinessurroundingthebonesaremainlylocatedalongthebackboneandtails.However,thelectureraddsthatfeathershavedis yfunctionbycitingthecaseofpeac