网址：http://m.1010jiajiao.com/timu3_id_2451663[举报]
Someone is ringing the doorbell. Go and see ＿＿＿＿＿＿.
A.who is he B.who he is
C.who is it D.who it is
A.who is he B.who he is C.who is it D.who it is