(1) 你是不是疯了?

Have you lost your mind? 或 Are you out of your mind?

(2) bear in mind that... 记住...

Bear in mind that your mon is coming tomorrow.

(3) slip my mind 忘了

Crap! That totally slipped my mind.

(4) cross my mind 想起，记起

That plan never crossed my mind.

(5) Out of sight, out of mind. 眼不见心不烦。

(6) Great minds think alike. 英雄所见略同。

(7) Mind your own business. 别多管闲事儿。

(8) Never mind. 没事。