21) No one realized ____ it was until much later.
A) how serious a crime
B) what serious a crime
C) how a serious crime
D) how a crime serious
22) On no condition ____ with him.
A) we cannot agree
B) would we agree
C) can we agree
D) we can agree
23) Factory workers have to work very hard, ____.
A) farmers do so
B) farmers work so
C) so hard farmers
D) so do farmers
24) Rarely ____ such a silly thing.
A) have I heard of
B) I have heard of
C) have I been heard of
D) I have been heard of
25) Not until I went to America ____ what kind of a country she is.
A) did I know
B) I know
C) I didn’t know
D) I could know
26) So instructive ____ the student wanted to see it again.
A) was the film
B) it was the film
C) the film was
D) the film it was
27) ____ a postgraduate, I would at least master two foreign languages.
A) Should I become
B) Were I to become
C) Had I become
D) I should become
28) Seldom ____ any mistakes during my past five years of teaching in this university.
A) would I make
B) I did make
C) should I make
D) did I make
29) ____ she would have avoided the accident.
A) She was more careful
B) If she was more careful
C) Had she been more careful
D) She had been more careful
30) ____ forget my hometown and my happy childhood.
A) Never I will
B) Never will I
C) Never I
D) I never have
责任编辑：wangpeng6151
