The doctor she sent her friend is very well known.A. by whomB. at whomC. whomD. to whom

问题补充：

The doctor she sent her friend is very well known.

A. by whom

B. at whom

C. whom

D. to whom

答案：

A. by whom

B. at whom

C. whom

(答案→)D. to whom

解析：考查定语从句中的介词搭配。本句中的to是动词短语send her friend to…中的介词。句意：她送她的朋友去的那个医生是很著名的。故D正确。