What is the rule?
You mustn't spit.
What is the rule?
You mustn't pick the flowers.
What is the rule?
You mustn't climb.
What is the rule?
You must line up.
What is the rule?
You must sit still.
What is the rule?
You must keep quiet.
What is the rule?
You mustn't litter.
What is the rule?
You must keep off the grass.
What is the rule?
You must wait for your turn.