4B must, have to, should KEY

a 2 mustn’t 3 don’t have to 4 both possible 5 should  6 doesn’t have to 7 mustn’t 8 mustn’t 9 should

b 2 mustn’t 3 don’t have to 4 must / have to  5 don’t have to 6 must / have to 7 mustn’t  8 must / have to