he finished writing his paper in such a short time surprised us all.A. WhenB. Why C. Tha

问题补充：

he finished writing his paper in such a short time surprised us all.

A. When

B. Why

C. That

D. What

答案：

A. When

B. Why

(答案→)C. That

D. What

解析：考查主语从句的连接词。That引导主语，在句中不充当任何成分，没有任何意思，只起连接作用，不能省略。When，why在句中都有实际的意思，what在句中要充当主语，宾语，表语或者同位语。结合句意可知C正确。句意：他在如此短的时间里写完了论文让我们都很惊讶。