Being angry is OK but knowing how to tell someone made you angry is important.A. that B.

问题补充：

Being angry is OK, but knowing how to tell someone made you angry is important.

A. that

B. which

C. why

D. what

答案：

A. that

B. which

C. why

(答案→)D. what

解析：D 考察名词性出引导词。Tell后面接双宾语，本句直接宾语是句子，句中却主语且为泛指。故what正确。