― Has Jackson finished his work today?
― I have no idea, but he it when I saw him this morning.
A. had done
B. would do
C. was doing
D. would have done
网友回答
A. had done
B. would do
(答案→)C. was doing
D. would have done
解析：考察时态.句意:今天杰克逊已经完成了他的工作吗?——我不知道，但是当我今天早晨看见他时他正在做。结合语境可知下文描述的是在过去某个时间正在进行的动作，故用过去进行时态。选C。