what has happened 中为什么要用has 而不用have

what has happened?为什么用HAS what happened what has happenedwhat happened what has happened 在语义上有什么区别吗 What has happened和What was happened区别 what happened ?和what has happened ?的区别 what has happened?I have said something unking to my friend.这句为什麽不用 what have happened what has happened 中为什么要用has 而不用have what has happened.这个句式有错吗 what has happened是什么时态的句型 what do you suppose _______to him?为什么是has happened不是to happen? I have no idea what has happened to him为什么是同位语从句 What do you imagine----to her?为什么是has happened?这算什么时态? do you know what ( ) just now.A.was happened B.happened C.has happened D.has been happened 是what has happened to还是what has happened at快,还有后面加什么! We haven't seen Jim for several days.What do you think has happened to him 为什么是has happened而不是will happen I have no idea what _____while I was asleep .A .has happened Bwas happened C.happened Dhad happened为神马选C呢?为神马ABD错的呢? what/that has happened.为什么是选what?happen后面不是不加宾语嘛?为什么不是that啊! what happened to you 和what has happened to you有什么区别 What has happened和What happened的区别另问过去时与现在完成时的区别