Unit4Globalwarming课时作业Ⅰ.阅读理解(2019·浙江高考)Californiahaslosthalfitsbigtreessincethe1930s,accordingtoastudytobepublishedTuesdayandclimatechangeseemstobeamajorfactor(因素)．Thenumberoftreeslargerthantwofeetacrosshasdeclinedby50percentonmorethan46,000squaremilesofCaliforniaforests,thenewstudyfinds.Noareawassparedorunaffected,fromthefoggynortherncoasttotheSierraNevadaMountainstotheSanGabrielsaboveLosAngeles.IntheSierrahighcountry,thenumberofbigtreeshasfallenbymorethan55percent;inpartsofsouthernCaliforniathedeclinewasnearly75percent.Manyfactorscontributedtothedecline,saidPatrickMcIntyre,anecologistwhowastheleadauthorofthestudy.Woodcutterstargetedbigtrees.Housingdevelopmentpushedintothewoods.AggressivewildfirecontrolhasleftCaliforniaforestscrowdedwithsmalltreesthatcompetewithbigtreesforresources(资源)．ButincomparingastudyofCaliforniaforestsdoneinthe1920sand1930swithanotheronebetween2001and2010,McIntyreandhiscolleaguesdocumentedawidespreaddeathofbigtreesthatwasevidenteveninwildlandsprotectedfromwoodcuttingordevelopment.Thelossofbigtreeswasgreatestinareaswheretreeshadsufferedthegreatestwatershortage.Theresearchersfiguredoutwaterstresswithacomputermodelthatcalculatedhowmuchwatertreesweregettingincomparisonwithhowmuchtheyneeded,takingintoaccountsuchthingsasrainfall,airtemperature,dampnessofsoil,andthetimingofsnowmelt(融雪)．Sincethe1930s,McIntyresaid,thebiggestfactorsdrivingupwaterstressinthestatehavebeenrisingtemperatures,whichcausetreestolosemorewatertotheair,andearliersnowmelt,whichreducesthewatersupplyavailabletotreesduringthedryseason.篇章导读：本文是一篇议论文。文章以加利福尼亚的大树从20世纪30年代以来大量减少为主题，探讨出这一现象的原因。1．Whatisthesecondparagraphmainlyabout?A．TheseriousnessofbigtreelossinCalifornia.B．TheincreasingvarietyofCaliforniabigtrees.C．ThedistributionofbigtreesinCaliforniaforests.D．TheinfluenceoffarmingonbigtreesinCalifornia.答案：A主旨大意题。第二段中通过列举一系列数字表明，加利福尼亚州的大树减少的严重性，故A项正确。2．Whichofthefollowingiswellintentionedbutmaybebadforbigtrees?A．Ecologicalstudiesofforests.B．Banningwoodcutting.C．Limitinghousingdevelopment.D．Firecontrolmeasures.答案：D推理判断题。文章第三段提到了造成加利福尼亚州的大树减少的三个因素：woodcutters，housingdevelopment与aggressivewildfirecontrol。前两个因素直接与大树的减少有关，如果能控制住，大树就不会减少；而第三个因素——控制野火的措施使得加利福尼亚州的森林里满是跟大树争夺资源的小树，初衷是为了控制野火，这是好的，实则对大树不利，故D项正确。3．WhatisamajorcauseofthewatershortageaccordingtoMcIntyre?A．Inadequatesnowmelt.B．Alongerdryseason.C．Awarmerclimate.D．Dampnessoftheair.答案：C细节理解题。根据文章最后一段中的“...thebiggestfactorsdrivingupwaterstressinthestatehavebeenrisingtemperatures...”可知，水资源不足的主要原因就是气温升高，即更加温暖的气候，故C项正确。4．Whatcanbeasuitabletitleforthetext?A．California'sForests：WhereHaveAlltheBigTreesGone?B．CuttingofBigTreestoBeProhibitedinCaliforniaSoonC．WhyAretheBigTreesImportanttoCaliforniaForests?D．PatrickMcIntyre：GrowMoreBigTreesinCalifornia答案：A标题判断题。本文是一篇调查报告，第一段就点出主题：Californiahaslosthalfitsbigtreessincethe1930s。后面具体分析了加利福尼亚州大树的现状、造成大树减少的原因等，故A项作为标题最合适。Intheatmosphere,carbondioxideallowsthesun'sraystoenterbutpreventstheheatfromescaping.Accordin...
