phones must be kept off _____ the talk

phones must be kept off _____ the talk --what else aren't allowed to do during the meating?--oh,all the mobile phones must( )A keep offB be kept offC keep onD be kept on 为什么是must be kept而不是must to be kept All the beepers and mobile phones must ___ in classA.keep off B.take off C.be taken off D.be kept off 初三英语单词填空?(首字母给出）My brother taught himself how to s______ the meeting.Mobile phones must be kept off d______ the meeting. all beepers and moble phones should be kept off during the meeting.keep Our room must ___ clean.A.keep B.be kept C.to be D.kept the room must be kept wet.变成被动语态! The medicine must be kept away from children翻译 翻译：The wheels of industry must be kept turning. What we talked must be kept private翻译 They urged that the library _________ open during the vacation.A.must be kept B.is kept C.would be kept D.be kept All the beepers and mobile phones must___ in class.A..keep off B.take off C.be taken off D.be kept off选什么?为什么 The medicine *cool,clean and dry.*处应选择哪个答案:A must keep B must be kept C must be carried D must be in This kind of food___cool,dry.A.shoud be placed B.must be kept选择哪个? Our room must ＿＿clean.A.keepB.be keptC.to be kept D.to keep The book ____ from the library must be kept well.The book ____(borrow) from the library must be kept well. It is desirable that the automation equipment_running as much of the time as possible.A.would be kept B.must be kept C.will be kept D.should be kept