Foreachblankinthefollowingpassage,therearefourchoicesgivenbelowandmarkedA,B,Cand D.ChoosetheonethatismostsuitableandmarkyouranswerbyblackeningthecorrespondingletterontheAnswerSheet. Smoking,whichmaybeapleasureforsomepeople,isaserioussourceofdiscomfortfortheirfellows._51_,medicalauthoritiesexpresstheirconcernabouttheeffectofsmoking_52_thehealthnotonlyofthosewhosmokebutalsoofthosewhodonot.Infact,non-smokerswhomustinvoluntarilyinhale(吸入)theair_53_bytobaccosmokemaysuffermorethanthesmokers_54_. Smokingisprohibitedinthetheatresandinhallsusedforshowingfilms_55_inlaboratories_56_theremaybeafirehazard(危险).Elsewhere,itisuptoyourgood_57_. Iam_58_askingyoutomaintain“No-Smoking”inclassroomsandseminarrooms. Thiswillprovethatyouhavethe_59_healthinmind,whichisveryimportanttoalarge_60_ofourstudents. __________