更新时间：2025-08-07 14:28:35
eachyearthereisanincreasingnumberofcarsontheroadsasmillionsofnewcarsareproduced.oneoutofsixamericansworksatmakingcars,drivingtrucks,buildingroadsorfillingupgas.americanscouldntlivewithoutcars!
mostamericanswouldfindithardtoimaginelifewithoutacar.however,somehaverealizedtheseriousproblemofairpollutioncausedbycars.thepollutedairbecomespoisonousanddangeroustohealth.
onewaytogetridofthepollutedairistomakeacarwithoutpollution.buttobuildacleancariseasiersaidthandone.progressinthisfieldisslow.
anotherwayistoreplacecarengineswithsomethingelse.inventorsarenowworkingonsteamcarsaswellaselectriccars.manymakersbelievethatitwilltakeyearstodevelopapracticalmodelforus.
topreventtheworldfrombeingpollutedbycars,wehavetomakesomechangesinourlives.americans,forexample,havetocutdownonthenumberoftheirtotalcars.theyareencouragedtousebicycles,whicharethoughttohelpkeeptheairclean.
butthischangedoesnotcomeeasily.alargenumberofworkersmayfindthemselveswithoutjobsifacarfactoryciosesdown.thustheproblemofairpollutionwouldbecomelessimportantthanthatofunemployment.althoughcarshaveledustoabetterlife,theyhavealsobroughtusnewproblems.
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