m4u2grammar(1)

in Beijing can cost a lot of money. Anybody can make mistakes． At that time we thought the story could not be true.
3)表示允许 Can (May) I come in ? Father said I could swim in the river.
4) 回答用语 ----May I come in? ----Yes, you may. ----No,you can’t / you may not ./you mustn’t/ you’d better not. 5)表祝愿 “may + 主语 + 动词原形” May God bless you ! May you succeed !
It is necessary that he should be sent there at once. It is strange that he should say so. 他会说这样的话真是奇怪。
1. There was a lot of fun at yesterday's party. You ___________ come, but why didn't you? A. must have B. should C. need have D.ought to have
may /might + have done 表示对过去发生的事 情的推测， “也许，可能” It may have been true. 这事也许是真的。 He might not have settled the question. 他可能尚未解决那个问题。 might have done可表示过去可能会发生而实 际上并未发生的事情。 That was too dangerous. You might have killed yourself. 那太危险了。你当时可能会丧命的。
3. must 1)表示必须、必要，多强调说话人的主观看法。 We must do everything step by step . 2) must的回答 ----Must I go tomorrow? ---- yes, you must. ---- No, you don’t have to. / No , you needn’t.
2. It's nearly seven o'clock. Jack ____ be here at any moment. (NMET'95) A.must B.need C.should D.can should表示推测。nearly 暗示“时间不早了”，Jack 按理应当随时都有可能到达这里; can表示推测时，常 用于否定句或疑问句中。
• What is modal verb? • What are the similar usages of modal verbs?
情态动词是表示能力,义务,必须,猜测等说话人的语气或情态 的动词.
情态动词不能单独做谓语，除ought和have外，后面只 能接不带to的不定式。
Step 4 exploration
5.shall的特殊用法 1) 用于第二，三人称的陈述句中，表允诺，警告， 命令或威胁。 Don’t worry, you shall have the tickets. He shall be punished. 他会受到惩罚的。 You shall do as you are told. 2) 在疑问句中，用于一，三人称表示征求意见或 向对方请示。 Shall we dance? Shall she go now?
3) must 表示肯定的推测 must do（目前状况的推测） must be doing （目前状况的推测） must have done （过去状况的推测）
He must be an honest boy. The road is wet. It must have rained last night. He must be working in his office. 与must 相对的否定推测用can‘t、couldn’t。 Mike can't have found his car, for he came to work by bus.
could语气更委婉 Could I use your bike? Could you speak a little slowly ?
4）can 表示推测时，不用于肯定句； can’t / couldn’t+ have done,表示对对过去的 事进行推测。couldn’t 的可能性比can’t小。
you should have worked hard. They should not have left so soon. 他们不应当走得这么早。（但已走了）
2)“It is natural (strange, necessary, surprised, impossible, important ) that sb should do sth， 表示“理所当然”、“奇怪”、“必要”、 “惊异”等的意思。
4. should / ought to 1. 应该, 应当 You don’t look well. You should / ought to go to see the doctor. You oughtn’t to smoke so much. Ought you to smoke so much ? 主要用法： 1)should have done / ought to have done,表示过去应 该做某事，事实上没有 should not have done / oughtn’t to have done
Can表示客观上能够，be able to表示具体做某 一件事的能力. be able to可用于各种时态，而 can只有一般现在时和一般过去时。
The child can speak English fluently。 When the boat sank he was able to swim to the bank.
1. He can’t/ couldn’t have finished so much work in so short a time.（表示对已发生的事情的推测） 2. You can’t be serious. （对现在情况的推测） 你不会是当真吧。
could+ have done,可表示过去有能力做某事， 但没做。（这属于虚拟语气，can无此用法）
Step 1 lead-in
Step 2 learning aims
1. To learn the general meanings and functions of modal verbs
2. To learn how to use several common modal verbs
Step 3 self-study
3.-I stayed at a hotel while in New York. -Oh, did you? You ___ with Barbara.(NMET'98) A.could have stayed B.could stay C.would stay D.must have stayed 4.My sister met him at the Grand Theatre yesterday afternoon, so he _________ your lecture.(2000上海)
1.I didn't hear the phone. I ____ asleep. A.must be B.must have been C.should be D.should have been 2.Johnny, you ______ play with the knife, you ______ hurt yourself.(NMET'96) A.won't; can't B.mustn't; may C.shouldn't; must D.can't; shouldn't 3.Put on more clothes. You _____ be feeling cold with only a shirt on. A.can B.could C.would D.must
强
ought to will must
4. To talk about permission may / might, can / could 5. To make requests will can could would
1．can / could 1) 表能力 I can climb this tree. He is only four , but he can read. I could swim when I was six.
4) must还可以表示“偏偏”，指令人不愉快的事。 Why must it rain on Sunday? 怎么偏偏星期天 下雨？ 5) must还可以表示必然的结果。 All men must die. 人固有一死。 If you don’t hurry, you must miss the train. 如果不快点，你必然要误车。 6) have to与must很接近,have to 强调客观需要， must着重主观看法。 I must clean the room. I have to clean the room. have to的否定形式为don’t have to“不必”，能 用于更多时态：has to / had to
A.couldn't have attended B.needn't have attended C.mustn't have attended D.shouldn't have attended