Question

― 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

C

解析：

根據(jù)題干，語(yǔ)境應(yīng)為“我不知道，今天早晨他還在做”，A為一般過(guò)去時(shí)，強(qiáng)調(diào)在過(guò)去

某一時(shí)間做某事，不強(qiáng)調(diào)結(jié)果；B為現(xiàn)在完成時(shí)，在過(guò)去發(fā)生，強(qiáng)調(diào)對(duì)現(xiàn)在的影響；C為過(guò)

去進(jìn)行時(shí)，指在過(guò)去某一時(shí)間正在做某事；D為過(guò)去完成時(shí)，表達(dá)過(guò)去的過(guò)去。所以C為正確答案。