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
Today Chinese ______ by more and more people all over the world.
Do you know how to use the computer?—Sorry, I don’t. Why ______ ask the teacher ______ help? [ ]
His grandparents live ____ in a small house, but they don’t feel _______.
What do you think of the students of Meiling Middle School?—They study _____ harder than before.[]
Where has your father gone? He has gone to Shanghai.And he’ll ______for three days.