Permission: May, Can

We use 'may' and 'can' to give or ask for permission. 'May' is more polite and formal than 'can'.

• You can have a cookie after dinner , son!
• You may have a cookie after dinner, son!
• May I sit here?
• Can I leave early?

And we use 'may not' or 'cannot' to deny permission.

• You may not have a cookie after dinner, son!
• You can't cross when the light is red.