I noticed the puzzled look on his face I realized that he didn’t understand me.A. Althoug

问题补充：

I noticed the puzzled look on his face, I realized that he didn’t understand me.

A. Although

B. When

C. Unless

D. Until

答案：

A. Although

(答案→)B. When

C. Unless

D. Until

解析：考查连词的辨析。 意为当我注意到他脸上迷惑的表情时，我意识到了他没有理解我的话。