1. Children can be careful when crossing the street.
2. There is plenty of time. We ___ hurry.
A.   can’t
B.   needn't
C.   may not
3. It’s a pity, I ___ translate this scientific article, as I have no dictionary with me.
A.   may not
B.   can’t
C.   mustn’t
4. George ___ go to the barbershop yesterday, because he was unwell.
A.   needn’t
B.   mustn’t
C.   couldn’t
5. It was far from the station and we ___ take a taxi home.
A.   might
B.   must
C.   had to