24. Tom was the only one of the boys who _____ praised by our teacher at the class meeting yesterday.

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

23. One-third of the area _____ covered with trees. About seventy percent of the trees _____ been planted recently.

　 　A. is; has　　　 　　　　　B. is; have　　 　　C. are; have　 　　　　D. are; has

22. --- I don’t know why he is late.

　--- Nor do I. He 　_____ an accident.

　 　A. could have had　　　　　 B. should have had 　　C. might have had　　　　　 D. must have had

21. --- Do you think he will help me?

　　 --- As far as I know, he is the last one to help others. He _____ be prepared to give you a hand, though.

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

20. It’s said that there are plenty of hotels in that town. There _____ be any difficulty for you to find somewhere to stay.

　　　 A. wouldn’t　　　　　　　 　B. mustn’t　　　 　C. shouldn’t　　　 　　　　 　D. needn’t

19. You _____ be tired; you have been working for so long a time, but he _____ be tired; he has just begun to work.

　 　　A. may not; must　 　　　　　 B. must; may not　 　　C. can’t; must　　 　　　　 　　D. must; can’t

18. --- Why do you ask me to do the difficult work?

　 --- Because you _____ do such a thing and nobody else is fit for it.

　 　　A. would　　　 　　　　B. can　　 　 　　　　　 C. should　　　　　 　　　 D. may

17. A hardworking man _____ become a great scientist, but a great scientist _____ be a hardworking man.

　　 A. can’t; can　　 　　　　　 　B. may not; can　 　　 　C. can’t; must　　　 　　　　 D. may not; must

16. We were all waiting for you; you _____ for the seaside by yourself without leaving a message.

　 　　A. mustn’t leave　　　　　　 　B. needn’t leave 　C. shouldn’t have left 　　　 D. couldn’t have left

15. You _____ be careful when you cross here --- the traffic lights aren’t working.

　　 　A. could 　　　 　　　　　 B. might　 　　 　　C. ought to　　　 　　　　D. may