Mr. Smith has been to many famous cities in China, Chengdu has impressed him most.
A. in which
B. on which
C. of which
D. with which
网友回答
A. in which
B. on which
(答案→)C. of which
D. with which
解析：考查介词前置的非限制性定语从句的用法，此处of意为：……之中的。Of which相当于of many cities意为：在许多城市中。Of many famous cities in China，Chengdu has impressed him most.句意：史密斯先生到过中国的许多著名城市，其中成都给他的印象最深。