For some time Chinese people under the leadership of CPC the contents of the Scientif

问题补充：

For some time, Chinese people, under the leadership of CPC, the contents of the Scientific Development Concept in the course of practicing socialism in China.

A. had been improving

B. have been improving

C. were improving

D. improved

答案：

A. had been improving

(答案→)B. have been improving

C. were improving

D. improved

解析：考察时态。根据句意可知是指中国人们一直在丰富这科学发展观的内容，故使用现在完成进行时，表示一直在发生的事情。句意：一直以来在中国共产党的领导下，中国人民一直在实践中国特色的社会主义道路上丰富着科学发展观的内容。