职称英语2011年版冲刺班讲义共26讲[1]

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1、本文由xianxuewu120贡献doc文档可能在WAP端浏览体验不佳。建议您优先选择TXT，或下载源文件到本机,查看。大家论坛club.topsage.com环球网校职称英语2011年版冲刺班讲义(1)第1课第五十篇：oldervolcaniceruptions(a级)综合远古火山喷发volcanoes,weremoredestructive破坏inancienthistory,notbecausetheywerebigg,er,butbecausethecarbon碳dioxide二氧化物theyreleas

2、edwiped擦去ou,tlifegreaterease.古代的火山更具杀伤力，不是因为它们更大，而是因为它们释,放出来的二氧化碳更容易把人杀死。paulwignallfromtheuniversityofleedswasinvestigatingthelink,betweenvolcaniceruptionsandmassextinctions.notallvolcaniceruption,skilledofflargenumbersofanimals,butallthemassextinctionsovert

3、,hepast300millionyearscoincidedwithhugeformationsofvolcanicrock.,tohissurprise,theolderthemassivevolcaniceruptionswere,themore,damagetheyseemedtodo.hecalculatedthe“killingefficiency功效”fo,rthesevolcanoesbycomparing比较theproportion比例oflifetheykille,doffwiththevo

4、lumeoflava熔岩thattheyproduced.他通过比较火山释放出,的熔岩的体积与杀死生命的比例计算这些火山的杀伤效力。hefoundthatsizefo,rsize,oldereruptionswereatleast10timesaseffectiveatwipingout,lifeastheirmorerecentrivals.thepermianextinction,forexample,whi,chhappened250millionyearsago,ismarkedbyfloodsofvol

5、canicrockin,siberiathatcoveranarearoughlythesizeofwesterneurope.thosevolc,anoesarethoughttohavepumpedoutabout10gigatonnesofcarbonascarb,ondioxide.theglobalwarmingthatfollowedwipedout80percentofall,marinegeneraatthetime,andittook5millionyearsfortheplanettor,ec

6、over.yet60millionyearsago,therewasanotherhugeamountofvolcani,cactivityandglobalwarmingbutnomassextinction.someanimalsdiddis,appearbutthingsreturnedtonormalwithintenthousandsofyears.“the,mostrecentoneshardlyhaveaneffectatall,”wignallsays.heignored,theextinctio

7、n消失whichwipedoutthedinosaurs65millionyearsago,be,causemanyscientistsbelieveitwasprimarilycausedbytheimpactofan,asteroid.hethinksthatoldervolcanoeshadmorekillingpowerbecausemo,rerecentlifeformswerebetteradaptedtodealingwithincreasedlevels,ofco.vincentcourtillo

8、t,directoroftheparisgeophysicalinstitutein,france,saysthatwignall’sideaisprovocative.buthesaysitisincre,diblyhardtodothesesortsofcalculations.hepointsoutthatthekilli,ngpowerofvolcanicerup