21. It's nearly seven o' clock. Jack ___ be here at any moment.

A. must　　　　 B. need　　　　　　 C. should　　　　　　 D. can

20. A computer ___ think for itself ; it must be told what to do.

A. can't　　　　B. couldn't　　　　 C. may not　　　　　　 D. might not　

19. The plant is dead . I ___ it more water.

A. will give　　　　　　　　　　　　　B. would have given

C. must give　　　　　　　　　　　　　 D. should have given

18. - I stayed at a hotel while in New York .

　　　 -Oh , did you ? You ____ with Barbara . (NMET98)

A. could have stayed　B. could stay C. would stay　　D. must have stayed

17. A dog ran in front of my mother's car and she ____ stop very quickly.

A. ought to　　 B. had better　　 C. must　　　　　　　 D. had to

16. A traffic accident happened yesterday and a driver ____ .

A. may hurt　　B. may be hurting C. may have been hurt　　D. may be hurt

15. I have neither a raincoat nor an umbrella. That's why I ____ wait until the rain stops.

A. must　　　 B. should　　　　　　　 C. ought to　　　 D. have to

14. I ____ tell her the truth.

A. cannot help　　B. can't but　 C. may not help　　　　D. could but

13. Sir, you ___ be sitting in this waiting room. It is for this woman and children only.

A. oughtn't to　　　　 B. can't　　　 C. won't　　　　 D. needn't

12. Johnny, you ___ play with the knife, you __ hurt yourself.

won't; can't　　　　　　 B. mustn't ; may　

C. shouldn't ; must　　　　　 D. can't ; shouldn't