To show degrees of permission, we can use various modal verbs.
You cannot leave yet.
You are not allowed to leave yet.
You may not leave yet.
You mustn’t leave yet.
You needn’t leave yet.
can is more friendly than may which is quite formal.
needn’t shows an action is optional – I can do it if I want to.
mustn’t states an action is forbidden – I have no choice.
2. Giving Orders
You will not leave yet.