你脑子进水了吗

Are you kidding?就可以表示这个一丝。

is there something wrong with your brain?

Are you stupid?
其实这句话算是中国俚语。。。通俗点讲大概就是你有病啊?

要表达这个意思的句子很多，但比较长常用的是are you crazy，man？

what the hell are you thinking

Is there something wrong with you?