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1、http://bailiedu.com老托福阅读真题PASSAGE77托福阅读的思维方式就是托福阅读的出题方式，只有掌握了这种思维方式，才有可能在做题之前，预测到新托福阅读题的出题形式和特点，为找答案节省时间。老托福阅读试题的核心价值，在于其最贴近真题的阅读思维方式。此外老托福阅读真题比新托福IBT阅读文章要短，比较容易适应。这也是大家在备考托福的时候非常重要的一点。因为前期的入手如果能从容易的开始，就会形成一个循序渐进的过程方式，让大家的练习有一个提高的过程。既然老托福阅读试题有这样的效果，那我们如何利用那有限的真题来达到锻炼
2、自己的目的呢？事实上这就一个办法，就是坚持。本期为大家推荐老托福阅读的真题PASSAGE77，附有原文及答案，希望对托福考生备考有所帮助。Itisestimatedthatover99percentofallspeciesthateverexistedhavebecomeextinct.Whatcausesextinction?Whenaspeciesisnolongeradaptedtoachangedenvironment,itmayperish.Theexactcausesofaspecies'deathvaryfroms
3、ituationtosituation.Rapidecologicalchangemayrenderanenvironmenthostiletoaspecies.Forexample,temperaturesmaychangeandaspeciesmaynotbeabletoadapt.Foodresourcesmaybeaffectedbyenvironmentalchanges,whichwillthencauseproblemsforaspeciesrequiringtheseresources.Otherspeciesm
4、aybecomebetteradaptedtoanenvironment,resultingincompetitionand,ultimately,inthedeathofaspecies.ThefossilrecordrevealsthatextinctionhasoccurredthroughoutthehistoryofEarth.Recentanalyseshavealsorevealedthatonsomeoccasionsmanyspeciesbecameextinctatthesametime—amassextin
5、ction.Oneofthebest-knownexamplesofmassextinctionoccurred65millionyearsagowiththedemiseofdinosaursandmanyotherformsoflife.Perhapsthelargestmassextinctionwastheonethatoccurred225millionyearsago,whenapproximately95percentofallspeciesdied,massextinctionscanbecausedbyarel
6、ativelyrapidchangeintheenvironmentandcanbeworsenedbythecloseinterrelationshipofmanyspecies.If,forexample,somethingweretohappentodestroymuchoftheplanktonintheoceans,thentheoxygencontentofEarthwoulddrop,affectionevenorganismsnotlivingintheoceans.Suchachangewouldprobabl
7、yleadtoamassextinction.Oneinteresting,andcontroversial,findingisthatextinctionsduringthepast250millionyearshavetendedtobemoreintenseevery26millionyears.ThisperiodicextinctionmightbeduetointersectionoftheEarth'sorbitwithacloudofcomets,butthistheoryispurelyspeculative.
8、Someresearchershavealsospeculatedthatextinctionmayoftenberandom.Thatis,certainspecieshttp://bailiedu.commaybeeliminatedandothersmay
