问题描述:
Did you see the accident ________when you were walking past?
A.to happen
B.happen
C.happened
D.is happening
选哪个,为什么
要专业,还有哪种情况和这个一样,举个例子.
A.to happen
B.happen
C.happened
D.is happening
选哪个,为什么
要专业,还有哪种情况和这个一样,举个例子.
问题解答:
我来补答展开全文阅读