1. 根据语境从方框中选择恰当的词语填空，有的需要变换形式，每个词语限用一次

must, could, don' t, can' t, let' s

1. （1） —Is that man your uncle over there?

   —It be him. He is in Beijing now.

3. （2） —Whose bike is this?

   —It be Mary's. In our class, only she rides to school.

5. （3） — go for a picnic tomorrow.

   —That' s a good idea.

7. （4）  talk loudly in public places, Jill. It's not polite.
9. （5） Therebe rain today so you'd better take an umbrella when you go out.