填空题
By the time you get to New York, I（）(已经动身去) London.
shall have left for
填空题 Why didn’t you tell me you could me the money? I（）(本来不必从银行借钱的）
填空题 The ship’s generator broke down and the pumps（）(不得不用手工操作) instead of mechanically.
填空题 It may be necessary to stop（）(每隔一定时间) in the learning process and go back to the difficult points in the lessons.
