GRAMMAR

情態(tài)動(dòng)詞（一）

【觀察】 請(qǐng)仔細(xì)觀察下列句子中情態(tài)動(dòng)詞的用法，并歸納總結(jié)。

1. ①Even top students can make mistakes in exams.

②Anna may know Tom’s address.

③If you’re not careful, you could get into trouble.

④Do you think Mr. Smith might be here on time?

⑤ — It must be our headmaster.

— No, it can’t be him. He has gone to Beijing. It may be Mr. Zhang.

⑥The rescue team should arrive by 5 o’clock this afternoon.

2. ① She can speak five languages.

② I couldn’t get tickets; they were sold out.

3. ① You can have my seat. I’m going now.

② Could I have a drink of water, please?   

③ — May I smoke here?

— Yes, of course.

④ Will / Would you please lend me your car tonight?

⑤ Shall we go out and have a walk after dinner?

⑥ Shall Tom go there with me tomorrow?

4. ① Ask, if you will, who the owner is.

② I would ask such questions when I was at school.

5. ① You shall be punished if you break the rule.

② Tell her that she shall have the bike tomorrow.

6. ① We should take good care of our children.

② You should give up smoking and drinking.

7．① All passengers must wear seat belts.

② You mustn’t move any of the books in my bag.

【自我歸納】

1. can / could, may / might, must / can’t, should都可表示可能性。

①can, may表示可能性的區(qū)別：can常用來(lái)表示理論上的、按常理推斷的抽象的可能性；may常用來(lái)表示實(shí)際的、馬上能應(yīng)驗(yàn)的具體的可能性。（如第1組第①②句）

②could, might表示推測(cè)時(shí)，并非表示過(guò)去，而表示可能性較弱。（如第1組第③④句）

③must表示推測(cè)時(shí)，語(yǔ)氣比較肯定，意為“肯定，一定”，其否定式多用_____。（如第1組第⑤句）

④should 用來(lái)表示一種估計(jì)的情況，可譯為“按理應(yīng)當(dāng)……，估計(jì)……”。（如第1組第⑥句）

2. can表示能力，could表示過(guò)去具有某種能力。（如第2組句子）

3. can表示許可或請(qǐng)求，可與may互換使用；will / would表示征求意見(jiàn)或提出請(qǐng)求，此時(shí)would并不表示過(guò)去，而表示委婉語(yǔ)氣；shall可以用于主語(yǔ)是第_____、三人稱的疑問(wèn)句，表示征求意見(jiàn)或許可。（如第3組第⑤⑥句）

4. will表示現(xiàn)在的習(xí)慣或意愿，would用于描述過(guò)去的習(xí)慣或例行的活動(dòng)，意為“過(guò)去常常”。（如第4組句子）

5. shall可用于主語(yǔ)是第二、三人稱的陳述句中，表示允諾、警告、命令或威脅等。（如第5組句子）

6. _____表示義務(wù)、責(zé)任或建議、勸告。（如第6組句子）

7. must表示“必須做某事”，其否定式_____表示“禁止”。（如第7組句子）

【知識(shí)拓展】

1. can表示“能夠”時(shí)與短語(yǔ)be able to同義，但can只用于一般現(xiàn)在時(shí)或過(guò)去時(shí)，而后者可用于各種時(shí)態(tài)。另外，can表示某人有某種能力，而be able to表示某人 通過(guò)努力、克服困難做成某事，相當(dāng)于succeed in doing sth.；敘述過(guò)去事實(shí)時(shí)，最好用was / were able to，因?yàn)?/span>could只表過(guò)去具有某種能力。如：

Can you understand the different kinds of English these people are using?

Two years later, he was able to speak very good Chinese.

2. 以could或would提問(wèn)時(shí)，就不能再以could或would作答，而應(yīng)該用can或will來(lái)回答。如：

— Could I borrow your dictionary?

— Yes, of course you can.

3. should用于why / how should ...或It’s + adj. + that ...句型中表示驚訝，譯為“竟會(huì)”。如：

I don’t know why she should have left her wallet behind.

It’s astonishing that he should be so rude to you.

4. 回答含must（必須）的問(wèn)句時(shí)，肯定回答用must，否定回答要用needn’t / don’t have to。如：

—Must I finish my homework at school?

—Yes, you must. / No, you needn’t / don’t have to.

5. could, might, would, should都可表示委婉語(yǔ)氣。如:

I wonder if you could let me use your cell phone.

Might I know your telephone number?

【同步練習(xí)】 

從A、B、C、D四個(gè)選項(xiàng)中，選出可以填入空白處的最佳選項(xiàng)。

1. —Shall I inform him of the change of the schedule right now?

—I am afraid you _____, in case he comes late for the meeting.

A. will       B. must       C. may     D. can

2. — No one _____ be compared with Yao Ming in playing basketball.

— Oh, you are really his big fan.

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

3. It _____ be the postman at the door. It’s only six o’clock.

A. mustn’t    B. can’t     C. won’t          D. needn’t

4. — Will you read me a story, Mummy?

— OK. You _____ have one if you go to bed as soon as possible.

A. might    B. must   C. could         D. shall

5. If you _____ smoke, please go outside.

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

6. The police still haven’t found the lost child, but they’re doing all they _____.

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

7. —Why didn’t you come to Simon’s party last night?

—I wanted to, but my mom simply _____ not let me out so late at night.

A. could     B. might       C. would         D. should

8. Just be patient. You _____ expect the world to change so soon.

A. can’t      B. needn’t    C. may not       D. will not

9. — I haven’t got the reference book yet, but I’ll have a test on the subject next month.

— Don’t worry. You _____ have it by Friday.

A. could        B. shall     C. must           D. may

10. Doctors say that exercise is important for health, but it _____ be regular exercise.

A. can        B. will        C. must           D. may

11.“You _____ have a wrong number,” she said. “There’s no one of that name here.”

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

12. —_____ I take the book out?

—I’m afraid not.

A. Will         B. May        C. Must            D. Need

13. The traffic is heavy these days. I _____ arrive a bit late, so could you save me a place?

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

14. One of the few things you _____ say about English people with certainty is that they talk a lot about the weather.

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

15. What do you mean, there are only ten tickets? There _____ be twelve.

A. should      B. would       C. will         D. shall    

Keys:

【自我歸納】 can’t;   一;  should;   mustn’t

【同步練習(xí)】

1-5 BABDC            6-10 ACABC          11-15 CBDDA