Thestudentfoundthenovel_______.Itprovidedhimwithsomuchinformationaboutthesubject.
WhenIcamethroughthecustomsattheairport,Ihadtopay________onaclockIhadbought.
ShegotajobasanassistantstagemanagerattheCambridgeArtsFestivalTheatre,thinkingthatitmight________toacareerasaplaywright(剧作家).
EachyearintheUnitedStates,manyblackteenagers_______ofschool,eitherbecausetheycannotkeepuportheyhavetoworktosupporttheirfamily.
Wemust______thattheexperimentiscontrolledasrigidlyaspossible.