【题目】Someone is ringing the doorbell，Go and see.
A.who is he
B.who he is
C.who is it
D.who it is

【答案】D
【解析】宾语从句的语序要用陈述语序.如果不清楚所谈到的那个人是男是女时,要用it来代替. it作人称代词,用来指代身份和性别等不明确的人。