问题补充:
--Do you know the man John Brown?
---I only know he is called.
A. called, how
B. called, what
C. who called, how
D. whom called, what
答案:
A. called, how
(答案→)B. called, what
C. who called, how
D. whom called, what
解析:called(=who is called)是过去分词作后置定语。