—Why do you look worried?— Because what I am really concerned about is my friend can do me

问题补充：

—Why do you look worried?

— Because what I am really concerned about is my friend can do me a favor or not..

A. although

B. whether

C. when

D. where

答案：

A. although

(答案→)B. whether

C. when

D. where

解析： 考查表语从句，句意：你为什么看起来很担忧？因为我的确关注的是我的朋友是否会帮助我还是不帮。根据句意应用关系词whether，选B。