lose one's marbles
marble 大理石
Hey, have you lost your marbles? Don't tell your girlfriend she's ugly.
你疯了么？别告诉你的女朋友她长得不好看。

Are you nuts?
nuts 坚果 nuts 发狂的；热衷的；狂热的

Sorry about that, my inner voice drives me nuts sometimes.
很抱歉，我的心声，有时候让我发狂。

go bananas 发疯，发狂
He is going bananas. 他疯了。

Are you crazy? 你疯了吗？
Liyang's Crazy Eenglish impresses us.
李阳的crazy English让crazy这个词深入人心。

Are you out of your mind?

Have you lost your mind?

Are you insane?