【三．阅读理解：（20×2.5=50分）Peoplehavesmokedcigarettesforalongtime.ThetobaccousedtomakecigaretteswasgrowninwhatisnowpartoftheUnitedStates.ChristopherColumbus,whodiscoveredAmerica,sawtheIndianssmoking,】

　　三．阅读理解：（20×2.5=50分）

　　Peoplehavesmokedcigarettesforalongtime.ThetobaccousedtomakecigaretteswasgrowninwhatisnowpartoftheUnitedStates.ChristopherColumbus,whodiscoveredAmerica,sawtheIndianssmoking,andsoonthedriedleavesweretransportedtoEuropewheresmokingbegantocatchon.Inthelate1800s,theTurk(土耳其人)madecigarettesevenpopular.

　　Cigarettessmokecontainsatleasttwoharmfulsubstances,tarandnicotine.Tar,whichformsasthetobaccoburns,damagesthelungsandthereforeaffectsbreathing.Nicotine,whichisfoundintheleaves,causesthehearttobeatfasterandincreasesbreathingrate.

　　Smokingcigarettesisdangerous.TheU.S.PublicHealthServicestatedthatcigarettesmokingisthecauseoflungcancersandseveralotherdeadlydiseases.TheU.S.governmentnowrequiresthateachpackageofcigarettesbear（带有）aspecialwarningaboutthedangerofsmoking.

　　1.Theexpression“catchon”inthepassagemaymean_________.

　　A.start B.costalot C.becomepopular D.dangerous

　　2.BeforeColumbusdiscoveredAmerica__________.

　　A.Europeanshadsmoked B.Nobodysmokedintheworld

　　C.Nicotinewasnotintobacco D.Europeanshadneversmoked

　　3.Inthenineteenthcenturysmokingbecamepopularbecauseofthepeoplein________.

　　A.India B.Turkey C.theU.S. D.British

　　4.Breathingisaffectedby___________.

　　A.nicotine B.tar C.heat D.bothAandB