What happened next?这句话对吗?为什么要用happened

what happened这个句子对吗 为什么 what happened?语法对吗 what happened to him yesterday.为什么要用happened?happen可以吗 “ What happened next?"算一个句子吗?为什么没有助动词? what has happened?为什么用HAS what happened what has happened what happened 为什么不可以用 what did happen what is happened with you 这句话有错吗? what happened in the street这句话正确吗 what do you think had happened to him. 这句话在语法上怎么用句 what happened about the cinema为什么用about不用 to what happened/what was happened/what is happened/what happen