I am sure he did is wise.A. thatB. about thatC. of thatD. that what

问题补充：

I am sure he did is wise.

A. that

B. about that

C. of that

D. that what

答案：

A. that

B. about that

C. of that

(答案→)D. that what

解析：考查从句关系词的选择。根据句型可知此处that what he did is wise是宾语从句，从句中what he did 作is wise 的主语，在主语从句what he did 中缺少did的宾语，所以选择what