Choose a,b or c
1. We ___ throw rubbish in rivers because the fish will die.
a. don’t have to
b. must
c. mustn’t

2. Ryan got up very early yesterday because he ____ be at the dentist’s at 7 o’clock.
a. has to
b. must
c. had to

3. It’s cold, so you ____ wait for me at the entrance. I’ll meet you inside the art gallery.
a. must
b. don’t have to
c. mustn’t

4. You ___ swim here. It’s dangerous.
a. don’t have to
b. can’t
c. have to

5. Martha can’t see well, so she __ wear glasses.
a. doesn’t have to
b. have to
c. had to

6. Iris had an accident. She ____ go to the doctor.
a. must
b. mustn’t
c. don’t have to