After several years he changed a lot and looked different from he used to be.A. whomB. wh

问题补充：

After several years, he changed a lot and looked different from he used to be.

A. whom

B. what

C. which

D. that

答案：

A. whom

(答案→)B. what

C. which

D. that

解析：考查名词性从句。句中what引导宾语从句，在从句中作表语，故选B。