1 . —Listen! Who is knocking at the door?_______ it be Alice?
—No, Alice has gone to town. It ________be Mary.（may/can）（用适当的词填空）

2 . Most doctors think people’s health_______ (可能) be closely related to their diet. （根据汉语提示单词拼写）

3 . The sugar in soft drinks forms acid and_______ (可能会) attack our teeth for about 20 minutes. （根据汉语提示单词拼写）

4 . It________ (可以) be said that the new film has attracted many adult audiences. （根据汉语提示单词拼写）

5 . 用方框内短语的适当形式填空

can，could，may，might，must

1. Helen ________ go on a trip with us, but she isn’t quite sure.
2. My sister met him at the theatre last night, so he ________ have attended your lecture.
3. —I am sure I saw Brian in the park this morning.
—You ________ be imagining things. He left for America last night.
4. —Is John coming by bus?
—He should, but he ________. He likes riding his bike.
5. —Isn’t that your teacher over there?
—No, it ________ be him. I’m sure he doesn’t wear glasses.

6 . Love is one of the greatest things in the world, but sometimes it ______ be difficult.

A．would

B．can

C．should

D．must

7 . William ________ be in the library at the moment, for I saw him playing basketball in the playground several minutes ago.

A．can’t

B．mustn’t

C．needn’t

D．wouldn’t

8 . China Hengda ________ have won the football match, but I’m not sure because I wasn’t there.

A．could

B．may

C．should

D．must