高一下学期情态动词

情态动词1.can/could/be able to 的用法

2.may/might 的用法

3.must/have to

的用法

4.will 与would的用法

5.shall 与should的用法

One of our rules is that every student （shall/ will）wear school uniform while at school.

Practice：在句中填入适当的情态动词

1.--- Can’t you stay a little longer?

---It’s getting late. I really go now. my daughter is home alone.

2.You feel all the training a waste of time, but I’m a hundred percent sure

later you’ll be grateful you did it.

3.It was so noisy that we hear ourselves speak.

4.You be careful with the camera. It costs!

5.I still remember my happy childhood when my mother take me to

Disneyland at weekends.

6.Since nobody gave him any help, he have done the research on his own.

7.My mom suggests that we eat out for a change this weekend.

8． I have a word with you? It won’t take long.

Keys: must; may(“不确定”可能)； couldn’t; must; would; must; should; Can 6.had better, ought to, need的用法

7.情态动词表示推测的用法

1）对不同时态的推测

“情态动词+do sth”

“情态动词+be doing sth”

“情态动词+have done sth”

eg: They must be in the classroom now.

The light in the teachers’ office is still on. Miss Gao must be working.

He must have finished his homework yesterday.

2)情态动词表示推测，在不同句型中的用法

1>在肯定句中，情态动词must,could,may,might等，肯定程度逐渐减弱

2>在否定句中使用can’t和may not/might not. can’t表示很有把握的否定推测，意为“不可能”；may not/might not表示不太有把握的否定推测，意为“可能不”

eg: She can’t be at school. It’s Sunday today.

She may not be there today.

I think he might not come.

3>在疑问句中，一般只用can或could,意为“可能”

Who can it be at the door? Can it be Tom?

Where could it be?

(注意：could 可用于肯定句、否定句和疑问句中表示推测；can只能用于疑问句和否定句中)

8.“情态动词+have done”的用法

1）would/could/should/might have done用在虚拟条件句中，如果表示与过去事实相反的情况，从句用过去完成时，而主句中则用“情态动词+have done”

If he had worked hard, he would have passed the Collage Entrance Examination.

2)must have done表示对过去已经发生过的情况的肯定推测，语气较强，意思为“一定···，肯定···”

It must have rained last night, for the ground is wet this morning.

(注意：否定句或疑问句中用must改为can或could)

3）may/might have done也用于对已经发生过的情况的肯定推测，但语气稍弱，意思是“可能，或许···”

She didn’t get there in time. She may have missed the bus.

4) should/ought to have done 表示过去应该做而（实际）没有做的事情，含有责备或遗憾的语气，意为“本应该···”；其否定形式为“should not/ ought not to have done”，表示某种行为不该发生但却发生了。

Jenny should have kept her word. I wonder why she changed her mind.

5)needn’t have done表示“过去没有必要做某事，但实际上却做了某事”

You needn’t have told that to him.

6)can/could have done 表示“过去本来可以做某事，但实际上没有做”；否定句表示“不可能已做了某事”；疑问句表示“可能/也许已做了某事吗？”

You could have come here a little earlier.

（注意：can have done 只能用于否定和疑问句中，而could have done则可以用于陈述、否定和疑问句中）

Practice: 选词填空——might/must/should/can/need (not)

1.I have watched that movie—it’ll give me horrible dreams.

2. It not be the postman at the door. It’s only six o’clock.

3. I have worried before I came to the new school, for my classmates here are very friendly.

4.—I don’t really like James. Why did you invite him?

—Don’t worry. He not come. He said he wasn’t certain what his plans were.

5. Harry is feeling uncomfortable. He have drunk too much at the party last night.

Keys: shouldn’t; can; needn’t; might; must

6.---Where Mary have put the empty bottles?

---She them away. They must be somewhere.

A.can; can’t have thrown

B.must; needn’t

C.must; must have thrown

D.can; mustn’t have thrown