You must help your mum.
You mustn't stand on the chair.
You must tidy your room.
You must go to bed early.
You must wear your boots.
You mustn't eat too much chocolate.
You mustn't be late.
You must keep your desk clean.
You must be kind to your friends.
You mustn't drop litter.
You mustn't shout in class.
You mustn't eat in bed.
You mustn't listen to loud music.
You must stay in your seat.
You mustn't jump the line.
You must knock on the door.