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1、智课网TOEFL备考资料新托福黄金精选阅读【PDF高清下载】摘要：新托福黄金精选阅读是2015年以来托福考试界最受欢迎的资料之一，究竟新托福黄金精选阅读的亮点在哪里，下面我们就来简单了解一下，同时有需要下载的小伙伴扫描页面中的二维码即可获得。新托福黄金精选阅读里面的真题全部来源于ETS官网，且每一篇文章都附有详细的解析和答案，对我们备考托福阅读非常有用.....,可以说新托福黄金精选阅读几乎是人手一本的精华资料。新托福黄金精选阅读：EuropaisthesmallestofplanetJupiter’sfourlargestmoonsandthesecondmoonout
2、fromJupiter.Until1979,itwasjustanotherastronomytextbookstatistic.Thencametheclose-upimagesobtainedbytheexploratoryspacecraftVoyager2,andwithindays,Europawastransformed-inourperception,atleast-intooneofthesolarsystem’smostintriguingworlds.Thebiggestinitialsurprisewasthealmosttotallackofdet
3、ail,especiallyfromfaraway.Evenatcloserange,theonlyvisiblefeaturesarethin,kinkedbrownlinesresemblingcracksinaneggshell.Andthisanalogyisnotfaroffthemark.ThesurfaceofEuropaisalmostpurewaterice,butanearlycompleteabsenceofcratersindicatesthatEuropa’ssurfaceiceresemblesEarth’sAntarcticicecap.Th
4、eeggshellanalogymaybequiteaccuratesincetheicecouldbeaslittleasafewkilometersthick–atrueshellaroundwhatislikelyasubsurfaceliquidoceanthat,inturn,encasesarockycore.TheinteriorofEuropahasbeenkeptwarmovertheeonsbytidalforcesgeneratedbythevaryinggravitationaltugsoftheotherbigmoonsastheywheelar
5、oundJupiter.ThetidesonEuropapullandrelaxinanendlesscycle.Theresultinginternalheatkeepswhatwouldotherwisebeicemeltedalmosttothesurface.ThecracklikemarksonEuropa’sicyfaceappeartobefractureswherewaterorslushoozesfrombelow.SoonafterVoyager2’sencounterwithJupiterin1979,whenthebestimagesofEurop
6、awereobtained,researchersadvancedthestartlingideathatEuropa’ssubsurfaceoceanmightharborlife.LifeprocessescouldhavebegunwhenJupiterwasreleasingavaststoreofinternalheat.Jupiter’searlyheatwasproducedbythecompressionofthematerialformingthegiantplanet.JustastheSunisfarlessradianttodaythanthepr
7、imalSun,sotheinternalheatgeneratedbyJupiterisminorcomparedtoitsformerintensity.Duringthiswarmphase,some4.6billionyearsago,Europa’soceanmayhavebeenliquidrighttothesurface,makingitacrucibleforlife.BothinwhatisnowtheeasternandthesouthwesternUnitedStates,thepeoplesofthe
