The engineer my father works is about 60 years old.A. to whomB. on whomC. with whomD. wit

问题补充：

The engineer my father works is about 60 years old.

A. to whom

B. on whom

C. with whom

D. with which

答案：

A. to whom

B. on whom

(答案→)C. with whom

D. with which

解析：句意：这个我父亲与之一起工作的工程师大约60岁了。这个句子中含有一个定语从句，work with sb.是固定用法，意思是与某人一起工作，且关系词指人，故用with whom，选C。