1. The bus driver looked over the engine carefully lest it _         _ on the way.

    A. breaks down     B. broke down    C. would break down  D. should break down

    2. Electronic computers must be made very small. Otherwise it_         _ impossible for them to be put in a communications satellite.

    A. be     B. is     C. would be     D. was

    3. They _         _ the problem easily if they had not acquired much fundamental scientific knowledge.

    A. hadn't solved    B. solved    C. wouldn't have solved    D. solve

    4. _         _he taken any precautions， the car would not have been damaged.

    A. Has     B. Should     C. Had     D. Were

    5. Mary would rather we_         _now， but we must go to work.

    A. didn't leave    B. not leave   C. had not left           D. not to be left

    6. She was very busy that day， otherwise she_         _in the contest.

    A. had taken part       B. would have taken part

    C. took part            D. would take part

    7. All this was ten years ago， but it seems as if it_         _only yesterday.

    A. is     B. were     C. be     D. was

    8. The manager of the club suggested that their regular meeting for this week_         _.

    A. was postponed              B. be postponed

    C. would be postponed         D. should postpone

    9. What do you think of her proposal that we_         _go out for a barbecue this weekend？

    A. will    B. should    C. has    D. have

    10. It is essential that the student _         _notes while listening to the lectures.

    A. took    B. takes    C. take    D. will take

    DCCCA BBBBC