新高考时文阅读7“好奇号”记录火星最大甲烷含量word版.docx

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1、时文拓展阅读“好奇号”记录火星最大甲烷含量自20世纪初期开始，人们凭着望远镜中看到的火星影像和头脑中的想象，认为火星上可能存在生命，乃至火星人。正是这种对神秘星球的无限遐想，促使人类一次一次地进行探索，一次一次地将遥远星际之外的秘密带回地球。最近“好奇号”又给人类历史上增添了怎样的光彩呢？一起来看看吧。阅读短文并回答问题NASA’sCuriosityvehiclerecentlyrecordedthelargestlevelofmethane（甲烷）evermeasuredduringitsseven-yearMarsmission.Th

2、ediscoveryisexcitingbecausetheexistenceofmethanegascouldsupportthecaseforlifeonMars.Methanehasnocolororsmell.AspecialinstrumentonCuriosity’sMarsScienceLaboratoryrecordedtheincreasedgaslevel.Thedevice,calledalaserspectrometer,measureslevelsofchemicalelementsandgasesintheMa

3、rtianatmosphere.Inadditiontomethane,theinstrumentcanrecordlevelsofwaterand CO2.NearlyallthemethanegasfoundinEarth’satmosphereisproducedbybiologicalactivity.Itusuallycomesfromanimalandplantlife.Butitcanalsobeformedbygeological（地质的）processes,suchasinteractionsbetweenrocksan

4、dwater.NASAsaidtheincreasedmethanewasmeasuredtobeabout21partsperbillionbyvolume(ppbv).OneppbvmeansthatifyoutakeavolumeofaironMars,onebillionthofthevolumeofairismethane. ItwasnotthefirsttimeCuriosityhasfoundmethanegasintheMartianatmosphere.Aboutayearago,NASAannouncedthatCu

5、riosityhaddiscoveredsharpseasonalincreasesinthegas. Thistime,NASAsaidthemeasuredmethanegaslevelwasclearlylargerthananyothersobservedinthepast.NASAofficialseventemporarilystoppedCuriosity’sotheractivitiestoinvestigatefurther. “It’sexcitingbecausemicrobial（微生物的）lifeisanimpo

6、rtantsourceofmethaneonEarth,”NASAsaidinastatementannouncingthediscovery.However,Curiosity’steamcarriedoutafollow-upmethaneexperimentthatshowedasharpdropinlevelsofthegas.Thesecondexaminationfoundthelevelwaslessthanonepartperbillionbyvolume.Thatnumberwasclosetothebackground

7、levelsCuriosityseesallthetime.TheriseandfallofthemethanegaslevelsleftNASAscientistswithmorequestionsthananswers.Thescientistsarecontinuingtostudypossiblecausesforthesuddenincrease.Themethanemysterycontinues.Curiositydoesnothaveinstrumentsthatcanexactlyidentifywhethertheso

8、urceofthemethaneisbiologicalorgeological.Oneleadingtheoryisthatmethaneisbeingreleasedfromundergr