我觉得可能是
Why did you do that? 吧 （一般过去时）
看你想表达什么了
也可以是 why are you doing that? （现在进行时）
why were you doing that?（过去进行时）
were是be动词are的过去式, 后面要加名词或动词ing
are后接did?没见过...

希望对你有帮助.