GRE历年题目解析.pdf

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1、14-7-2710:15PM第一：我用的这套gre历年真题是陈琦团队整理的，如有不妥，请告知我，随时撤下。第二：按照这套真题的顺序，由简入难，从最简单的level1开始，我将努力分析每篇阅读，并及时发上来，但是其中有些文章肯定会有分析错误，所以请大家帮我提出来，大家一起讨论，这才是我发这个贴的主要目的。第三：分析当中涉及一些概念:TW主题词，TS主题句，KW论点，abcdefg….都为说明性内容或者论据。1.Themoleculesofcarbondioxide1ThemoleculesofcarbondioxideintheEarth’satmosphereaffectth

2、eheatbalanceoftheEarthbyactingasaone-wayscreen.2Althoughthesemoleculesallowradiationatvisiblewavelengths,wheremostoftheenergyofsunlightisconcentrated,topassthrough,theyabsorbsomeofthelonger-wavelength,infraredemissionsradiatedfromtheEarth’ssurface,radiationthatwouldotherwisebetransmittedbackintos

3、pace.3FortheEarthtomaintainaconstantaveragetemperature,suchemissionsfromtheplanetmustbalanceincomingsolarradiation.4Iftherewerenocarbondioxideintheatmosphere,heatwouldescapefromtheEarthmuchmoreeasily.5Thesurfacetemperaturewouldbesomuchlowerthattheoceansmightbeasolidmassofice.1Today,however,thepot

4、entialproblemistoomuchcarbondioxide.2Theburningoffossilfuelsandtheclearingofforestshaveincreasedatmosphericcarbondioxidebyabout15percentinthelasthundredyears,andwecontinuetoaddcarbondioxidetotheatmosphere.3Couldtheincreaseincarbondioxidecauseaglobalriseinaveragetemperature,andcouldsucharisehavese

5、riousconsequencesforhumansociety?4Mathematicalmodelsthatallowustocalculatetheriseintemperatureasafunctionoftheincreaseindicatethattheanswerisprobablyyes.1Underpresentconditionsatemperatureof-18℃canbeobservedatanaltitudeof5to6kilometersabovetheEarth.2Belowthisaltitude(calledtheradiatinglevel),thet

6、emperatureincreasesbyabout6℃perkilometerapproachingtheEarth’ssurface,wheretheaveragetemperatureisabout15℃.3Anincreaseintheamountofcarbondioxidemeansthattherearemoremoleculesofcarbondioxidetoabsorbinfraredradiation.4Asthecapacityoftheatmospheretoabsorbinfraredradiationincreases,theradiatinglevelan

7、dthetemperatureofthesurfacemustrise.1Onemathematicalmodelpredictsthatdoublingtheatmosphericcarbondioxidewouldraisetheglobalmeansurfacetemperatureby2.5℃.2Thismodelassumesthattheatmosphere’srelativehumidityremainsconstan