1 . People liked O. Henry’s stories, because simple as the tales were, they ______ finish with a sudden change at the end, to the readers’ surprise.

A．could

B．would

C．might

D．must

2 . 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

3 . 从行为心理学分析，他奇怪的行为可能源于他最近的压力。(account)
From the perspective of behavioral psychology, ________________.

4 . —He ______be in the classroom. I think.
—No, he ______ be in the classroom. I saw him go home a minute ago.

A．can; may not

B．must; may not

C．may; can’t

D．may; mustn’t

5 . — Where are you going for your holidays this summer?
— Well, it’s not been decided. I ______go to the countryside to see my parents.

A．might

B．need

C．can

D．must

6 . You ________ walk on the wet hill path because you ________ fall and hurt yourself.

A．must; might not

B．mustn’t; might

C．needn’t; need

D．must; must

7 . — He is a very good tennis player; you __________ see him in action.
— Thanks for your advice.

A．are able to

B．ought to

C．mustn't

D．might not

8 . — Is Lang Lang going to perform at Art Center this Friday?
— Yes. It ________ be him. He has been here for three days.

A．might

B．must

C．mustn’t

D．may

9 . —Who’s that person in the street? Is it Mr. Liu?
—It ________ be him. Because Mr. Liu is ill in hospital already.

A．mustn’t

B．can’t

C．needn’t

D．maybe