what is happening 和 What is happened和 what had hwhat is happening 和 What is happened和 what had happend 这三个对吗?对的话有什么区别

问题描述:

what is happening 和 What is happened和 what had h
what is happening 和 What is happened和 what had happend 这三个对吗?对的话有什么区别

只有第三个是对的

我认为What happend才对,意思是 怎么了?/发生什么了?

第三个是对的,意思是:已经发生了什么?