简介:Longlongago,ourworldwasverybeautiful,thereweretrees,flowers,rivers...theywereverycleanandtidy.Butnow,thehillsarenrtgreen,theriversaren'tclean,thefishhasdied.Pollutionisbecomingmoreandmoreseriousallovertheworld.Wearelivinginapollutedenvironmentwhichisbadforourhealth.