what happened /what has hanppend/what has been haapening

what happened /what has hanppend/what has been haapening what happened what has happened what has happened是什么意思 what has happened? 是what has happened to还是what has happened at what has happened to you what has happened?为什么用HAS what happened ?和what has happened ?的区别 What has happened和What was happened区别 what had happened和 what has happened有什么区别 What has happened和What happened的区别 “what has been up to