1 You don’t need to / mustn’t touch the exhibits. It’s
not allowed.
2 She can’t / doesn’t have to come with us if she
prefers to stay at home. It’s fine.
3 We mustn’t / must hurry! The train leaves in a few
minutes.
4 Martin must / can go to the cinema, but he has to
come back home before midnight.
5 You don’t need to / mustn’t buy a ticket today,
the entrance is free.