Grammar and usage(2): Modal verbs: comparisons优秀教案内容

情态动词 一、情态动词

知识构建

情态动词不能独立作谓语，需与其后动词原形一起构成谓语部分；情态动词没有人称和数的变化；情态动词 + do / be表现在或将来的动作或状态，情态动词 + have (been) done表过去动作或状态，情态动词 + be doing表推测现在或将来正在进行的动作。

常见的情态动词的词义和相关结构如下表所示：

考点归纳

一、can, could 与be able to的用法

1. can / could用来表示“一般能力”，如凭借体力、脑力或技能去做某事；be able to有多种时态，且用来表示在特定条件下的“具体能力”，尤其指通过努力才能做成某事。

My grandma is over seventy, but she can still read without glasses.

He was able to flee Europe before the war broke out.

2. can / could表示惊讶，常用在否定句和疑问句中。

How can you treat me like that?

3. can / could表示礼貌地请求别人做某事，意为“能，可以”。与man/might意义相近。

Can / May I have a word with you? It won’t take long.

二、may与might

1. 表示允许，意为“可以，许可”，用法基本上同can与could。

May / Can I use your bicycle?

2. 表示可能性，意为“也许，可能”。

According to the weather forecast, it may rain tomorrow.

3. may可以放在句首，表示祝愿。用may+动词原形，may须置于句首＝I wish you…

May you succeed!

三、must

must表示义务、命令或必要，意为“必须”，它的否定形式mustn’t表示“禁止”，表示说话者的命令或指令，语气比较强烈。“must + 动词原形”表示对现在情况的推测；“must be + 现在分词”表示对现在正在进行中的事的推测；“must have + 过去分词”表示对过去的推测。注意：must表推测时只能用于肯定句中。

Since nobody gave him any help, he must have done the research on his own. 因为没有人给他任何帮助，他肯定靠自己做的那项研究。

四、shall

1. 用于第一、第三人称的疑问句中，用来征求对方的意见或请求指示。

Shall we begin our new lesson today?

2. 用于第二、第三人称的陈述句中，表示说话人的意愿，有“命令、警告、允诺、威胁、强制”等意思。

You shall be punished for what you have done.

五、should

should表示劝告/建议/责任时，意为“应当”，常用于suggest/advise等引导的宾语从句当中；表惊讶/遗憾, 意为“竟然/居然”，常用在I’m surprised; It worried me; It’s a pity; You can’t imagine等结构中；should(n’t) have done表示对过去的虚拟，意为“本该（不该）做某事而实际没做（做了）”。

I find it quite astonishing that you should be so rude to your mother.

Our English teacher suggests that we should speak English every day.

I’m feeling sick and I shouldn’t have eaten so much chocolate. 我现在觉得不舒服，我不该吃那么多巧克力的。

六、would

would可表示过去反复发生的动作或某种倾向，常与every day, often, frequently等连用；would表示估计、猜想，或在虚拟结构中用于对过去或将来的假设或愿望。

I still remember my happy childhood when my mother would often take me to Disneyland.

This printer is of good quality. If it should break down within the first year, we would repair it at our expense.

七、情态动词 + have done

其用法归纳如下

八、常见的一些情态动词的固定结构

1. can’t…too / over = can’t…adj. /adv. enough

再…也不过分

2. can’t help/choose but do…

不得不做…

3. can’t help doing

情不自禁做（但can’t help to do意为“帮不上忙”）

4. can’t / couldn’t agree more

十分赞成

5. It can’t / couldn’t be better

十分好，非常好

6. It can’t be denied that…

不可否认的是…

7. can’t wait to do

迫不及待做某事

8. won’t / can’t have... doing

不能容忍做某事

9. may / might as well do 最好，倒不如

10. may / might well do 很可能

强化训练

一、语法填空：在空白处填入适当的内容(一个单词)或括号内单词的正确形式。

1. Why ________ you tell me about your trouble last week？If you ________ (tell) me, I could have helped.

2. We ________ have faced the ________ (difficult) together, but why didn’t you tell me?

3. I wish that you________ (have) such a bad headache because I am sure that you would have enjoyed the concert.

4. When Edison died, it was suggested that the American people ________ (switch) off all power for several minutes, ________ suggested that people ________ (show) respect for this great man. 5. We would rather our daughter ________ (stay) at home with us, but it’s her choice, and she is not a child any longer.

6. If only I________ (forget) to send Maggie an e-mail telling her my arrival time yesterday. If so, she could meet us at the airport.

7. If he ________ (spend)more time practising speaking English before, he ________ (be) able to speak it much better now.

8. Forgive me for being so rude, Jim. I ________ have shouted at you.

9. ________ he caught the morning train, he wouldn’t have been late for the meeting.

10. We ________ (lose)our way in that small village, otherwise we would ________ (visit) more places of interest yesterday.

11. With the presidents of two countries ________ (force) to resign, more leaders have realized it’s high time they ________ (attach) importance ________ economy and political freedom.

12. Sorry, I am too busy now. If I ________ (have) time, I would ________ (certain) go for an outing with you.

13. I quarreled with my grandfather again ________ drinking. Because his doctor recommended that he________ (reduce) the amount of alcohol every day. 14. It can’t ________ (deny) that protecting the environment is of great ________ (important).

15. The boss couldn’t have him ________ (get) away with stealing in his supermarket, and he insisted the thief________ (arrest)and put into prison.

二、单句改错：每句错误最多有两处。错误涉及一个单词的增加、删除和修改。

1. Life today will be very different if Thomas Edison hadn’t invented the electric light.

2. I’d rather you didn’t told me about it the other day.

3. If you listened to the doctor, you would be all right now.

4. But for the rain, we should have a pleasant journey.

5. If only I have read the books on reading list before I attended the lecture.

6. It was advised that we observed carefully while conducted experiments in the lab. 7. Have he not broken the rules , he wouldn’t have fallen behind, it annoyed his mother.

8. She mustn’t have left school, for her bike is still here.

9. I needn’t worried after I came to the new school, for my classmates here are very friendly to me.

10. The commander ordered that the wounded would be sent in hospital right away.

三、翻译

1. 该是我们采取行动减少污染的时候了。

2. 要是我能像你一样知道如何操作这台电脑就好了。

3. 要不是这个过路人的帮助，这个女孩可能已经淹死了。

4. 因为在下倾盆大雨，你最好待在家里。

5. 你本来可以做得更好的，但是当时你太粗心了。

6. 如果我们当时早一点订位子的话，我们现在就不会还在排队了。

7. 如果昨天你来了的话，你就可以看见他了。

8. 我真希望没有告诉妈妈我的考试成绩。

9. 她妈妈建议她去看医生。

10. 我迫不及待地回到家去读那本妈妈送给我的书。

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参考答案：

一、填空

1. didn’t; had told 2. could; difficulty 3. hadn’t had

4. (should) switch; which; showed 5. stayed 6. hadn’t forgotten

7. had spent; would be 8. shouldn’t

9. had 10. lost; have visited 11. forced; attached / should attach; to 12. had; certainly 13. about/over; should reduce 14. be denied; importance 15. getting; should be arrested 二、改错

1. will - would

2. didn’t - hadn’t

3. listened前加had

4. have后加had 5. have - had

6. observed - observe; conducted - conducting 7. have - had; it-which或it前加and

8. mustn’t - can’t

9. worried前加have；after-before

10. would - should; in - to 三、翻译

1. It’s high time that we should take measures to reduce pollution.

2. If only I knew how to operate the computer as you do. 3. But for the passer-by’s help, the girl could have been drowned.

4. Now that it’s raining cats and dogs, you may/might as well stay at home.

5. You could have done better, but you were too careless. 6. If we had booked a table earlier, we wouldn’t be standing in a queue now. 7. If you had come yesterday, you could have met him. 8. I wish I had not told my mother the result of the exam.

9. Her mother suggested that she should go and see the doctor. 10. I can’t wait to go home to read the book that my mother bought for me.