Question

(经典回放)－Has Sam finished his homework today?

－I have no idea．He ________ it this morning．

[　　]

A．

did

B．

has done

C．

was doing

D．

had done

Answer 1

答案：C
解析：

此题语境设计非常精彩，句意是：“Sam做完作业了吗?”“我不知道。他今天早晨正在做。”本题考查的是过去某个时间正在做的事情，所以选择C项。