Unit 3 On screen, 3D Grammar, must, mustn’t and needn’t / don’t have to, page 33
Exercise 1
1 must
2 have to
3 mustn’t
4 don’t have to
5 have to
6 must
7 needn’t
8 mustn’t
Exercise 2
1 doesn’t have to
2 mustn’t
3 mustn’t
4 doesn’t have to
5 mustn’t
6 mustn’t
7 don’t have to, mustn’t
Exercise 3
1 don’t have to / needn’t
2 mustn’t
3 must / have to
4 must / have to
5 mustn’t
Exercise 4
1 must
2 must
3 have to
4 must
5 have to