题目内容：

--Hello,I'd like to speak to John,please.
--_____
A：No,I'm Mary.
B：This is Mary speaking.
C：It's him here.
D：This is him.

优质解答

回答电话,一半用this is或it is +sb speaking,所以这题选B

追问：

D为啥不行

追答：

him不对啊