The editor-in chief asked me to write an article for him about AIDS patients in China.A.

问题补充：

The editor-in chief asked me to write an article for him, about AIDS patients in China.

A. that

B. one

C. it

D. this

答案：

A. that

(答案→)B. one

C. it

D. this

解析：

试题分析: 句意：——主编让我为他写一篇文章，一篇关于中国AIDS病人的文章。由结构可知此处是同位语，解释说明an article的内容，四个选项中只有one可以做同位语，选B。