Grammar can -I believe the man is from England. -But I may be wrong. The guest may arrive this afternoon表示猜测答语避免使用may，以免显得 太严肃或太不客气The road may be blocked. 这条路可能不通了。 The road can be blocked. 这条路可能会是不通的。 在疑问句中，表示可能性用can。如：Where can he be? 他会在哪呢？可能性从大到小: must. can could may mightC. _May you succeed! May you have a good journey! 表示祝愿;语气较正式:多在间接引语中表示过去的可能和允许。也可以表示现在的可能性，但是比may 表示的可能性更小，且might可以用于虚拟 语气，may不可以。might 的用法有:She said that he might take her bike. 她说他可以拿她的自行车去用。You might get some help from her if she were here.will wouldntB. May; had better notC. Must; mustntD. Need; mustntB2. -Where is Emma?-I cant say for sure where she is, but she_ be out shopping.A. canB. shouldC. mustD. mayD3. The room is in a terrible mess; it _ cleaned.A. cant have beenB. couldnt beC. may have beenD. would beA4. How_ you say that you really understand the whole story if you have covered only part of the article?A. canB. mustC. needD. mayA5. What does the sign over there read? “No person _ smoke or carry a lighted cigarette, cigar or pipe in this areas.” A. Will B. may C. shall D. mustC6.Has Mr. Tom White arrived?Yes, already _he wait outside or just come in? A.Shall B. May C. Could D. MustA7. -Jane has just come back from China and she looks happy.- She _ her trip very much.A.must enjoy B. must have enjoyedC. may enjoy D should have enjoyedB8. You cant imagine that a well-behaved gentleman _ be so rude to a lady. A.might B. need C. should D. would C表示惊讶的语气9. The terrible accident is under investigation.Actually , quicker action _those workers trapped in the mine.A. might have saved B. must have savedC. should have saved D. could have saved D10. He chose to teach in a western province,though he _in the city for a better life. A. could stay B. would stay C. could have stayed D. had stayedC11. We _ here at lunch time ; we were delayed at the airport, though.A. could be B. should be C. must have been D. would have beenD12. How I wish I _ my mouth before I shouted at my um !A. shut B. have shut C. had shut D. would shut C13. We must apply what we have learnt to our daily work because in no case _from practice. A. should theory separate B. should theory be separated C. theory should separate D. theory should be separatedB14. Who has made a mess in my room? Who else _it but your naughty son? A. could do B. could have done C. should do D. Should have doneB15. Its really a wonder that all the passengerson board _ while the plane itself sank intothe freezing Hudson River in New York. A.must have been saved B. should have been saved C. would be saved D. might be savedB16. You _ late for yesterday class meeting ,as it was so important. A.couldnt be B. shouldnt be C. mustnt have been D. oughtnt to have been17. But for your timely warning, we _intogreat trouble.You know were friends. A.would get B. must have got C. would have got D. cant have gotDC