V. Choose the appropriate modal verb.

1. John _____ go to the dentist because he had a toothache.

a) must b) should c) had to

2. You _______ stay in the foreign country longer than your visa allows.

a) needn't b) mustn't c) shouldn't

3. We ________ help our granny to do the housework.

a) should b) may c) are able to

4. At the airport your luggage ______ be lost.

a) must b) can c) should

5. You ________ talk aloud in the reading-hall.

a) can't b) mustn't c) needn't

6. Cats _______ see very well in the dark.

a) should b) have to c) can