问题

Look, so many people are running out of the station. I wonder what ______ .
A:is happened
B:was happening
C:is happening
D:had happened;
B:was happening
C:is happening
D:had happened;
正确答案是:
同类题型
_____ofthe two story books are very interesting, so I can’t decide whichone to choose.
Quzhou is a beautiful city. Every year there are__________ tourists.
The hotel is almost finished, but it _____ needs one or two weeks to get ready for guests [ ]
Perhaps more people will travel in our city__________in the future.
The reason ________ he gave for his being away for such a long time is ________ his mother was ill.