托福写作冲刺王2web网智课课网

2121综合写作之高分要点—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综合写作之范文模仿—TPO3TherearethreeargumentsagainstthefactthatthefinelinessurroundingtheskeletonbonesofSinosauropteryxarefeathers.However,thelecturerthinksnoneofthemareconvincing.First,thepassageholdsthatthefinelinesarejustskinfibers posedfromadeaddinosaur,andthelinesdonotrepresentfunctionalstructuresofalivingdinosaur.However,thelecturerclaimsthatthefinelinesarenotskinfibersbecausethereisnosuch positionfoundinotheranimal’sfossilsatthesamesite.What’smore,thebeautifully functionalskinstructureswerediscoveredinotheranimal’sfossilsatthesamesite.ThatprobablymeanstheSinosauropteryx’slinesmayalsobefunctionalstructurelikefeathers.22综合写作之范文模仿—TPO3Thelectureralsochallengesthesecondargumentthatthelinesaroundtheskeletonarefossilizedremainsoffrillsratherthanremainsoffeathers.Accordingtothelecturer,featherscontainagreatamountofBeat-keratin,atypeofprotein,whichfrillsdonothave.AndsinceBeat-keratincanbefoundinSinosauropteryxstructures,thestructurescanonlybefeathers,butnotfrills.Finally,thepassageassertsthatthestructurerepresentedbylinesdoesnothavefeathers’practicalfunctionslikeflightandthermoregulation,becausethelinessurroundingthebonesaremainlylocatedalongthebackboneandtails.However,thelectureraddsthatfeathershavedis yfunctionbycitingthecaseofpeac