小学、初中、高中各种试卷真题知识归纳文案合同PPT等免费下载www.doc985.com选择性必修三Unit3拔卷选（考试时间：75分钟试卷满分：100分）第一部分阅读理解(共两节，满分50分)第一节（共15小题；每小题2.5分，满分37.5分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项。AScientistsinMexicosaytheymayhavefoundawaytocuttheproductionofmethane(甲烷),agaslinkedtorisingtemperaturesontheEarth’ssurface.Thescientistssaytheirmethodmayhelpreducethemethanereleasedbycows,oneofthemainproducersofthegas.Whentalkingaboutglobalwarming,manypeoplethinkofcarbondioxide,anotherheat-trappinggas.Methaneisanevenmorepowerfulheat-trappinggas.Cowsareknowntoproducehighlevelsofmethanewhentheyeatandprocessfood.ResearchersattheAutonomousUniversityoftheStateofMexicoarestudyinghowacow'sdietaffectstheproductionofmethane.Theresearchersareusingaspeciallydesignedmachinetomeasuretheeffect.Thescientistsusethemachinetotrytocapturetheanimal'sbreathingtoexaminethemethanereleased.Mostofthegasisreleasedwhencowsbelch.Thedigestivebacteriainacow'sstomachcausestheanimaltosendoutthegasthroughitsmouth.Thereareanestimated1.3to1.5billioncowsintheworld.Eachanimalreleasesasmuchas120kilogramsofmethaneperyear.TheU.S.EnvironmentalProtectionAgencyreportsthat,whenevermeasuredinpounds,theeffectofmethaneonclimatechangeismorethan25timesgreaterthancarbondioxideovera100-yearperiod.Asitisdifficulttocapturethegasreleasedbycowsforuseasenergy,onewaytolessenitsreleaseistochangetheirdiet.Scientistsinsomecountriesarelookingforwaystodecreasecowmethane.Butwhiletheyaretryingdifferentplantsandchemicalcompounds,thoseproductswouldbetoocostlyanddifficulttobringtoMexico.1.Howharmfulisthegassentoffbycows?A.Itismoredifficulttocontrolitsamount.B.Ittakesupmostofhuman-causedmethane.C.Itisthekeyfactortopreventglobewarming.小学、初中、高中各种试卷真题知识归纳文案合同PPT等免费下载www.doc985.com小学、初中、高中各种试卷真题知识归纳文案合同PPT等免费下载www.doc985.comD.Itismoreharmfulthancarbondioxide.2.Whatcanscientistsinsomecountriesdotosettletheproblemcausedbycows?A.Limitthenumberofcows.B.Changewhattheyeat.C.Fixmachinesontheirmouths.D.Usetheirgasesasenergy.3.Whatmaybethebesttitleforthetext?A.WeHadaBetterMethodofRaisingCowsB.CowsAreMuchMoreHarmfulthanCarsC.ResearchersFoundaWaytoReduceMethanefromcowsD.TwoGasesAreCausingtheWarmingofthePlanet【答案】1.D2.B3.C【解析】【导语】本文是一篇说明文，介绍了研究人员发现了一种减少奶牛体内甲烷的方法。【1题详解】细节理解题。根据第二段“Whentalkingaboutglobalwarming,manypeoplethinkofcarbondioxide,anotherheat-trappinggas.Methaneisanevenmorepowerfulheat-trappinggas.”（当谈到全球变暖，许多人想到另一种吸热气体——二氧化碳，但甲烷是一种更强的吸热气体）可知，甲烷比二氧化碳更能导致全球变暖，故选D。【2题详解】细节理解题。根据最后一段“Asitisdifficulttocapturethegasreleasedbycowsforuseasenergy,onewaytolessenitsreleaseistochangetheirdiet.”（由于很难捕获奶牛释放的气体作为能量，减少其释放的一种方法是改变它们的饮食）可知，一些科学家可以通过改变奶牛的饮食来减少其甲烷排放量，故选B。【3题详解】主旨大意题。根据第一段“ScientistsinMexicosaytheymayhavefoundawaytocuttheproductionofmethane(甲烷),agaslinkedtorisingtemperaturesontheEarth’ssurface.Thescientistssaytheirmethodmayhelpreducethemethanereleasedbycows,oneofthemainproducersofthegas.”（墨西哥科学家表示，他们可能已经找到了一种减少甲烷产生的方法，甲烷是一种与地球表面温度升高有关的气体。科学家们...