别提了 / 别提多…了【bié tí le / bié tí duō … le】

别提了 – literally "don't mention it" – answers a question about something that went badly. It tells the listener the story is not a happy one, and the speaker usually goes on to tell it anyway.

别提多…了

With 多 and an adjective inside, the frame means "you can't imagine how ...". Here it works for good things as well as bad.

The final 了 is part of the frame.

• × 别提多高兴 → 别提多高兴了

Not a reply to thanks

English "don't mention it" answers thanks. 别提了 never does; it would sound as if the favour had gone wrong. After 谢谢, say 不客气 or 没事.

• × A：谢谢你！B：别提了 → A：谢谢你！B：不客气