用在肯定句中：

对过去的推测：

may /might have +PP(过去分词)

must have +pp(过去分词)

对现在的推测：

must be + noun / adj.

may be/ must be + v-ing

must +v(原形)

用在否定句中

对过去的推测：

can't have + PP(过去分词)

对现在的推测：

can't be + noun / adj.

can't +v(原形)

Do the exercise 7, 8 and 9 to practise and consolidate modal verbs

Do some Best Choice to consolidate modal verbs

1. -Do you know where David is? I couldn't find him anywhere.

--Well. He _____ have gone far-his coat's still here.

A. shouldn't B. mustn't

C. can't D. wouldn't

2 ---Excuse me. Is this the right way to the Summer Palace?

---Sorry, I am not sure. But it _____ be.

A. might B. will

C. must D. can

3. ---Tom graduated from college at a very young age.

--- Oh, he _____ have been a very smart boy then.

A. could B. should

C. might D. must

4. ---I heard they went skiing in the mountains last winter.

---- It ____ true because there was little snow there.