he has done it is surprising. he has done is surprising.A. WhatB. ThatC. WhetherD. If

问题补充：

he has done it is surprising.

he has done is surprising.

A. What

B. That

C. Whether

D. If

答案：

A. What

(答案→)B. That

C. Whether

D. If

解析：A.第一句意义完整,所以用That引导主语从句.第二句do需带宾语,所以用What引导主语从句.