Our kind teacher wanted to teach us he knew about this lesson.A. thatB. that allC. every

问题补充：

Our kind teacher wanted to teach us he knew about this lesson.

A. that

B. that all

C. everything which

D. what

答案：

A. that

B. that all

C. everything which

(答案→)D. what

解析：what引导的是表语从句。