13. "We    the train had we left earlier," the wife complained to the husband.

A. wouldn't miss    B.   wouldn't have missed

C. would miss     D.   would have missed

12. The boy's parents    the operation last week had it not been for the donations from our school. 

A.    couldn't have paid for

B.    couldn't pay for

C.    shouldn't have paid for

D.    wouldn't pay for

5. Many people have come to realize that they should go on__________ balanced diet and make room in their day exercise.

4. —Shall I give you a ride as you live so far away?
―Thank you. It __________ be better.

11. —Show me your permit, please.

―Oh, it's not in my pocket. It    .

A.    must have fallen out

B.    might fall out

C.    could fall out

D.    should have fallen out

3. Nuclear science should be developed to benefit the people __________ than harm them.

2. Although he is often tired __________ his work, he is never tired his job. In fact, he enjoys it.

根据语境用适当的词填空（每空只填一词）

1. You are working too hard. You'd better keep a balance__________ work and relaxation.

10. ―It is unbelievable that John should have fought with the policeman.

―Well, if one     ask for trouble, it just can't be helped.

A. will    B. must

C. should     D. dare

9.  ―I don't know what I    without the suitcase you lent me.

―Glad to have been of some help to you.

 A. should have done  B. would do  C. would have done   D.  should do