1. It may be necessary to stop__________________________(每隔...时间) in the learning process and go back to the difficult points in the lessons.
2. The mad man was put in the soft-padded cell lest he ______________(伤害自己).
3.Jean did not have time to go to the concert last night because she was_______________(忙着准备) her examination.
4. The ship's generator broke down and the pumps____________________(不得不用手工操作) instead of mechanically.
5. Why didn't you tell me you could me the money? I___________________________ (本来不必从银行借钱的) 221
参考答案：
1. at intervals
2. injure himself
3. busy preparing for
4. had to be operated manually
5. needn't have borrowed it from the bank.
