1. () no electronic computers , they could have been no satellites orrockets.

√A. Had there been B. If there were

C. Should there be D. If there are

省略if的倒装;

2. Hardly had Professor Birch finished his speech () the audiences

started cheering.

A. as B. that C. since √D. when

否定词前置的倒装，如hardly , never , on no account , scarcely ,

in no case , no sooner , not until , not only , rarely , seldom , little 等;

3. Never () such a marvelous place as the Great Wall before I got there.

A. did I see B. I had seen C. I saw √D. had I seen

4. On no account () there.

A. you should go B. you must go

C. had you to go √D. must you go

5. () ,Sam would have been able to pass the exam.

A. If he studies more B. If he were studying to a greater degree

C. Studying more √D. Had he studies more