【单选题】You don’t believe he will give up smoking, ____?
【单选题】从哪一年开始,中俄之间有了官方的外交联系?()
【单选题】If you don't , you are sure to succeed. [ ]
【单选题】To 'stick to something' means that you continue to do it and don’t ______.
【单选题】当机构运动行程速比系数K()时,可在从动曲柄上使其顺利通过死点位置。
【单选题】Don't give up any hope, ________?
【单选题】When you don't know what to do next, never give up, just ______. working out your problem.