I have been living in London for more than ten years so I have good knowledge of this ci

问题补充：

I have been living in London for more than ten years, so I have good knowledge of this city.

A. /

B. the

C. a

D. an

答案：

A. /

B. the

C. a

D. an

解析：句意：我住在伦敦10多年了，我对这个城市非常了解。knowledge,名词，知道，了解，have a good knowledge of是一个固定短语，对……非常了解，故选C。