Who is _____ ( knock It is me.

Who is _____ ( knock It is me. 解释下这句话Knock,knock jokesKnock,knock jokes是现在美国人长说的,原台词是knock,knock,knock,who is there? this flowerpot is broken .who knocked it___ knock over knock off 有什么区别 , Who is hungry?_____ 为什么是is knocking：Who is knocking(knock) at the door?it's me. someone（ ）（knock）at the door．Go and see who it is Who is calling? = who is ____ _____? Who is that boy _____ _____?He is Li Ming. —There is a knock at the door.—---------------?A.who is that?B.who can it be?...—There is a knock at the door.—---------------?A.who is that?B.who can it be?C.who is he?D.do you think who he is?a和c为什么不对啊 ( )_____ is she?_____mother is she?A whose;who B who;who C who;whose _____(who) school bag is heavier Who is _____(calm) ,Lucy or Lily Who is_______(knock)on the door? Who is_______(knock)on the door? knock knock knock knock