Withmoreandmorecarsontheroad，thetrafficjamwillhappen.Howdoweseeitandhowcanwesolvetheproblem?Weknowthatthetrafficjamhappensinmanyplaces,especiallyinbigcities.Whatarereasonsfortheproblem?Ontheonehand，somepeoplethinkthattheyshouldhaveacarwhentheyhaveenoughmoney,andthenit'seasytogooutandtheycanfeelcomfortable.Ontheotherhand,agrowingnumberofpeoplehopetousetheircarstoshowoff.What’smore,yearsofresearchhasshownthatoneofotherreasonsforthetrafficjamisthedrivinghabit.Forexample,manyyoungpeopleenjoydrivingveryfast,sotheycanfeelexcited.Atlast,mostofthemhardlycareaboutthespeedrules.Manygovernmentsareworkingathowtomakethetrafficbetter．Inmyopinion,firstly,thegovernmentsshouldeducatethosepeoplewhohavecarsorplantobuycars.Thegovernmentsmustmakethemknowthatthetrafficjamisveryserious,andsetupamuchmoreperfecttrafficsystemtosolvethetrafficpressure.36.Whatdoestheunderlinedword"jam"meaninChinese?
Cantreestalk?Yes,butnotinwords.Scientistshavereasontobelievethattreesdocommunicatewitheachother.Notlongago,researcherslearnedsomesurprisingthings.Firstawillowtreeattackedinthewoodsbycaterpillars(毛虫)changedthechemistryofitsleavesandmadetheirtastesoterriblethattheygottiredoftheleavesandstoppedeatingthem.Thenevenmoreastonishing,thetreesentoutaspecialsmell----asignal(信号)causingitsneighborstochangethechemistryoftheirownleavesandmakethemlesstasty.Communication,ofcourse,doesn'tneedtobeinwords.Wecantalktoeachotherbysmiling,raisingourshouldersandmovingourhands.Weknowthatbirdsandanimalsuseawholevocabularyofsongs,soundsandmovements.Beesdancetheirsignals,flyingincertainpatternsthattellotherbeeswheretofindnectar(花蜜)forhoney.Sowhyshouldn'ttreeshavewaysofsendingmessage?31.Itcanbeconcludedfromthepassagethatcaterpillarsdonotfeedonleavesthat______.