问题

What _____ Kathy fell and hurt her knee?[ ]
A: weather
B: whether
C: through
D: if
B: whether
C: through
D: if
正确答案是:
同类题型
Which floor does John live on? — He lives on the __________floor of the building.
It was the third time that the boy _________ late. So his teacher got very angry.
You an umbrella. Do you think we are going to have rain today? —. I use it as a walking stick.