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 . —_________I go with my friends to the harvest festival?
—No. you’d better not.

A．Must

B．May

C．Would

D．Need

3 . Both drivers and passengers         wear seat belts while their cars are running on the highway.

A．must

B．can

C．may

D．need

4 . In order to make our dreams come true, we _______ work hard.

A．must

B．can

C．need

D．may

5 . I guess this book ______ be Mary’s, but I’m not sure.

A．must

B．mustn’t

C．may

D．can

6 . Public health experts kept telling citizens it was of utmost importance that social distancing and hygiene habits ________ amid the pandemic.

A．were to be kept	B．had to be kept
C．must be kept	D．should be kept

7 . — ________ we take the subway to the airport now?
—I think so. The traffic ________ be very heavy at this time of the day.

A．Must, must

B．can, can’t

C．can’t, may

8 . —Mom,_____I hang out with Susan now?
—No,you_____.It’s dangerous for two girls to be outside at night.

A．could;can’t

B．could;needn’t

C．should;can’t

D．must;couldn’t

9 . 用can或must填空
1. My phone ________have been stolen while I was taking a bus. I can't find it anywhere.
2. I'm hungry. I ________eat two bowls of rice now.
3. You not ________touch other people's head in this country as it will, according to local people, bring had luck to both of you.
4. —Why________ you stay in the countryside where it's not convenient to go shopping?
—Because I've found it beneficial to my health.
5. As far as I am concerned, the air crash ________not have been caused by a bomb attack.
6. You________ not be tired—you've only been working for ten minutes.
7. It is usually warm in my hometown in March, but it________ be rather cold sometimes.
8. Many rare animals are dying out. We________ find ways to protect our environment.

10 . 选词填空must/have to
1. He missed the bus and __________ walk home.
2. You _________ pay the money, but you needn’t do so at once.