You are not to... 不准你……
"are not to..."的含义接近"should not / ought not to / must not"，是禁止别人干某事的意思。
1. You are not to smoke in this room.
2. You are not to use mobile phones in the hospital.
3. You are not to go out alone in the future.
A: May I see your daughter please?
B: My daughter is very upset now.
A: Please just give me a chance. I want to talk to her.
B: I'm sorry but you're not to see her again.