3 . Hiking trips ________ sound exciting to most kids, but few realize they ________ be uncomfortable and even dangerous.

A．would; should

B．must; should

C．may; can

D．can; will

5 . As we all know, very loud noise ________ make people sick or drive them mad.

A．should

B．need

C．can

D．must

7 . —Tony, is that Mr. Black over there?
—I knew that he had gone to England. It          be him.

A．might

B．could

C．can’t

D．must

8 . —Look! Someone is coming towards us. It must be Mrs. Zhang.
—No. It ________ (not) be her. She is on holiday in another city these days.(所给词的适当形式填空)

9 . 选词填空。
1. My mother is ill, so I ________(have to/ must)stay home to look after her.
2. He ________(can’t/ mustn’t)be Tom. Tom has gone to London, you know.
3. It’s dark outside. Besides, it’s raining heavily. So, you ________(had better/ might)go home with me.
4. In today’s information age, the loss of data ________(can/must)cause serious problems for a company.
5. It’s strange that he ________(should/ must)have taken the books without the owner’s permission.
6. Samuel, the tallest boy in our class, ________(can/should)easily reach the books on the top shelf.
7. My room is in a mess, but I ________(needn’t/ shouldn’t)clean it before I go out tonight. I can do it in the morning.