雅思阅读真题演练 熟悉文章结构与出题规律

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1、智课网雅思备考资料雅思阅读真题演练熟悉文章结构与出题规律雅思阅读的文章和题目都有一定的规律性，比如说雅思阅读文段一般是总分总的格式，考生重点关注首段，尾段，转折句，开头句，基本上就能找到主题句，从这个方面来说，练习雅思阅读真题，从中总结雅思阅读考试经验是十分必要的。雅思阅读的文章和题目都有一定的规律性，比如说雅思阅读文段一般是总分总的格式，考生重点关注首段，尾段，转折句，开头句，基本上就能找到主题句，从这个方面来说，练习雅思阅读真题，从中总结雅思阅读考试经验是十分必要的，下面小编为大家整理一份“TPO雅思阅读真题答案及解析”，希望对大家有所帮助。雅思阅读真题：Th

2、eLong-TermStabilityofEcosystemsPlantcommunitiesassemblethemselvesflexibly,andtheirparticularstructuredependsonthespecifichistoryofthearea.Ecologistsusetheterm“succession”torefertothechangesthathappeninplantcommunitiesandecosystemsovertime.Thefirstcommunityinasuccessioniscalledapioneer

3、community,whilethelong-livedcommunityattheendofsuccessioniscalledaclimaxcommunity.Pioneerandsuccessionalplantcommunitiesaresaidtochangeoverperiodsfrom1to500years.Thesechanges—inplantnumbersandthemixofspecies—arecumulative.Climaxcommunitiesthemselveschangebutoverperiodsoftimegreatertha

4、nabout500years.Anecologistwhostudiesapondtodaymaywellfinditrelativelyunchangedinayear’stime.Individualfishmaybereplaced,butthenumberoffishwilltendtobethesamefromoneyeartothenext.Wecansaythatthepropertiesofanecosystemaremorestablethantheindividualorganismsthatcomposetheecosystem.Atonet

5、ime,ecologistsbelievedthatspeciesdiversitymadeecosystemsstable.Theybelievedthatthegreaterthediversitythemorestabletheecosystem.Supportforthisideacamefromtheobservationthatlong-lastingclimaxcommunitiesusuallyhavemorecomplexfoodwebsandmorespeciesdiversitythanpioneercommunities.Ecologist

6、sconcludedthattheapparentstabilityofclimaxecosystemsdependedontheircomplexity.Totakeanextremeexample,farmlandsdominatedbyasinglecroparesounstablethatoneyearofbadweatherortheinvasionofasinglepestcandestroytheentirecrop.Incontrast,acomplexclimaxcommunity,suchasatemperateforest,willtoler

7、ateconsiderabledamagefromweathertopests.Thequestionofecosystemstabilityiscomplicated,however.Thefirstproblemisthatecologistsdonotallagreewhat“stability”means.Stabilitycanbedefinedassimplylackofchange.Inthatcase,theclimaxcommunitywouldbeconsideredthemoststable,since,bydefinition,itchan

8、gesth