6 He had been working for more than 11 hours. He... Be tried now
A need. B. Had better. C must. D must not
7 In this city, people... Walk on grass
A coldn't. B mustn't. C needn't. D may not
8 children... Swallow small object
A may. B must. C need. D must't
9 driver... Stop when the traffic lights are red
A must. B could. C may. D might
10 there is no... To ask for his permission because we can decide it on own
A should. B must. C need. D have to
11 Vietnamese students ( must/ have to) wear uniform when they go to school
12 if there are no taxis we'll ( must/have to ) walk
13 you really (must /have to ) hurry up. We don't want to the be late
14 I have a bad toothache. I(must/have to) make an appointment with the dentist
15she (must /have to) work on Saturday morning
16 don't make so much noise. We (mustn't /don't have to) wake.