Friendship helps us understandwe are we need each other andwe can do for each other.A. wh

问题补充：

Friendship helps us understandwe are, we need each other andwe can do for each other.

A. what; why; how

B. who; how; what

C. who; what; why

D. who; why; what

答案：

A. what; why; how

B. who; how; what

C. who; what; why

(答案→)D. who; why; what

解析：考察宾语从句。Understand后面有3个宾语从句：who we are(我们是谁；who做表语);what we need(我们需要的东西；what做need的宾语)；what we can do(我们能做的；what做do的宾语)；故D正确。