[简答]  二、阅读理解：阅读下面的短文，根据文章内容从A、B、C三个选项中选出一个最佳选项。AirpollutionPeopleandairpollutionareofteninthesameplaces.Thismeansthatcitieswithlargepopulationshave thebiggestproblemofdirtyair.Airpollutioniscausedbymanydifferentthings.Amajorkindofair pollutionisthegasfromcars.Statistics(统计资料)showthat93percentofallautotripsarewithincities.Anothermajorkindofdirtyairistheburningofcoalandoilforenergy.Thisenergyisneededtomake electricity.Ofcourse,muchmoreelectricityisusedinthecitythaninthecountry.Ontheaverage,wethrowawaymorerubbishthantheyearbefore.Theburningofrubbishmakesair pollutionevenworse.Manymajorindustriesarealsoresponsibleforthedirtyairinthearoundcities.The fumes(烟)fromiron,steel,chemical,andpetrolproductionaddparticles(微粒)  totheair.Theeffectsofairpollutionrangefrommildheadachestodeath.Thelevelsofpollutionfoundinheavy trafficmaycauseheadachesforlossofclearvision.Wherevercoalandoilareusedforfuel,fumesmay killtreesandplantsandcausemetaltocorrode(腐蚀).Insomeofthelargercities,thesefumesendanger thelivesofhumanbeingsbycontributingtolungdiseasesandcausingearlydeath.1.Thekeypointofthepassageisthat.A．thecauseofairpollutionispeopleB．thecausesandtheeffectsofairpollutionarebothfoundincitiesC．theeffectsofairpollutionrangefromheadachestodeath2.Whatisthepurposeofthispassage?A．topersuadepeopletostoppollutingtheairB．totellthecausesofairpollutionC．totellwhycitiesarebadplacestolive3.Whyisairpollutionmoregraveinthecitythaninthecountry?A．Becausetherearelargerpopulationsincities.B．Becausetheairinthecityisdirty.C．Becausetherearemuchmoregasfumesfromcarsandburningofcoalandoilforenergyinthecitythaninthecountry.4.Thefumesfromcoalandoilmaycausemetal.A．tocorrode           B．totwist              C．toturnblack5.Inlargercities,thefumesfromcoalandoilmaycontributeto.A．heartdisease       B．lossofclearvision          C．lungdiseases