课后限时作业(八)限时/50分钟Ⅰ.阅读理解Plantsarefloweringfasterthanscientistspredictedinreactiontoclimatechange,whichcouldhavelongdamagingeffectsonfoodchainsandecosystems.Globalwarmingishavingagreateffectonhundredsofplantandanimalspeciesaroundtheworld,changingsomelivingpatterns,scientistssay.Increasedcarbondioxide(CO2)intheairfromburningcoalandoilcanhaveaneffectonhowplantsproduceoxygen,whilehighertemperaturesandchangeablerainfallpatternscanchangetheirpatternsofgrowth.“Predictingspecies'reactiontoclimatechangeisamajorchallengeinecology，”saidtheresearchesofseveralU．S.universities.Theysaidplantshadbeenthekeyobjectofstudybecausetheirreactiontoclimatechangecouldhaveaneffectonfoodchainsandecosystemservices.Thestudy,publishedontheNaturewebsite,usesthefindingsfromplantlifecyclestudiesandexperimentsacrossfourcontinentsand1,634species.Itfoundthatsomeexperimentshadunderestimated(低估)thespeedoffloweringby8.5timesandleafingby4times.“Acrossallspecies,theexperimentsunderpredictedthespeedoftheadvance—forbothleafingandflowering—thatresultsfromtemperatureincreases，”thestudysaid.Thedesignoffutureexperimentsmayneedtobeimprovedtobetterpredicthowplantswillreacttoclimatechange,itsaid.PlantsarenecessaryforlifeontheEarth.Theyarethebaseofthefoodchain,usingphotosynthesis(光合作用)toproducesugarfromcarbondioxideandwater.Theyletoutoxygenwhichisneededbynearlyeveryorganismontheplanet.Scientistsbelievetheworld'saveragetemperaturehasrisenbyabout0.8℃since1900,andnearly0.2℃everytenyearssince1979.Sofar,effortstocutemissions(排放)ofplanetwarminggreenhousegasesarenotseenasenoughtopreventtheEarthheatingupbeyond2℃thiscentury—apointscientistssaywillbringthedangerofachangeableclimateinwhichweatherextremesarecommon,leadingtodrought,floods,cropfailuresandrisingsealevels.语篇导读本文为说明文，介绍了全球变暖的气候环境会让植物提前生长开花，进而影响整个食物链及生态系统。1．WhatisthekeyinformationtheauthorwantstogiveinParagraph1?A．Plants'reactiontoweathercouldhavedamagingeffectsonecosystem.B．Theincreasingspeedoffloweringisbeyondscientists'expectation.C．Climatechangeleadstothechangeoffoodproductionpatterns.D．Foodchainshavebeenseriouslydamagedbecauseofweather.解析B细节理解题。根据第一段可知，作者是要告知读者植物开花的增速超出了科学家的预期，故选B项。2．WhatcanwelearnfromthestudypublishedontheNaturewebsite?A．Plants'floweringis8.5timesfasterthanleafing.B．Thereare1,634plantspeciesonthefourcontinents.C．Scientistsshouldimprovethedesignoftheirexperiments.D．Theexperimentsfailedtopredicthowplantsreacttoclimatechange.解析C推理判断题。根据第五段第二句可推出，对于植物所设计的实验应该有所改进，故选C项。3．Whydoscientistspayspecialattentiontothestudyofplants?A．Becausetheycanprovetheclimatechangeclearly.B．Becausetheyareveryimportantinthefoodchains.C．Becausetheyplayaleadingroleinreducingglobalwarming.D．Becausetheyaregrowingandfloweringmuchfasterthanbefore.解析B细节理解题。根据第四段第二句可知，植物对气候变化的反应对整个食物链和生态系统都至关重要，故选B项。4．Whatcanbeinferredfromthelasttwoparagraphsabouttheworld'stemperature?A．Ithasrisennearly0.2℃since1979.B．Itschangewillleadtoweatherextremes.C．Itis0.8℃higherin1979thanthatof1990.D．Theriseofthetemperatureneedstobecontrolledwithin2℃inthiscentury.解析D推理判断题。根据最后一段可知，如果本世纪地球变暖超过2℃，便会出现极端天气，由此可推出，这个世纪地球温度的...
