what was happening?happening词性

what was happening?happening词性 What _______last night?A.happened B.is happening C.was happened D.was happening He didn't know what was happening outside,为什么happening是进行时? it appeared that he didn't know what was happening=he()()to know what was happening what happens what was happened what happens what is happening的区别和用法? He demanded that we explain what was happening,________?为什么不是He demanded that we explained what had been happening,---? jerry asked his mother what was happening jerry asked his mother what was _____ _____ i()with my father at that time.i didnt know what ()A.was swimming;was happening B.am swimming;has happenedC.was swimming;happened D.swam;was happening what happened/what was happened/what is happened/what happen/what is happeniwhat happened/what was happened/what is happened/what happen/what is happening这些用法都有吗 —Susan stays alone in the classroom and looks sad—______to her?A.what happens B.what has happened C.what is happening D.what was happening The man hurried there to see what was happening还是what has happened what is happening 歌词 what's happening there What happening with you? （What's happening? 英语翻译1What was happening when two of the detectives opened the parcel?2What was happening when the plane arrived? DO you know ____over there A.what happening B.what was happened C.what is happeningD,what did happen What in your neighborhood this time yesterdayA.happened B.was happened C.was happening D.is happening需要原因.具体点啊