Is Lucy knocking at the door?No.It _____ be Lucy.She is in Japan now.

Is Lucy knocking at the door?No.It _____ be Lucy.She is in Japan now. someone is knocking at the door.It might be the posyman.为什么用is knocking 为什么是is knocking：Who is knocking(knock) at the door?it's me. Someone is knocking at the door.____ is it? There is someone knocking at the door.为什么用“knocking”,要加“ing”? Listen!_______(有人）is knocking at the door. Someone is knocking at the door,but who can____ be? 单句改错 who is the men knocking at the door Someone is knocking at the door.同义句改写：There is ___ ___ at the door. Someone is knocking at the door._must be TomSomeone is knocking at the door._must be Tom A.that B.It C.He D.This who is knocking at the door?A.This is me knockingB.It's me. There is somebody knocking at the door .Go to see( ) it is. who is knocking at the door?it is ()me还是i呢?求理由 It is impolite to come into the office without ( )the doorA.knock B.knocking at C.to knock at D.knocking to someone is knocking at the door.who [ ]it be?A;mustB;canCmayD;shall必须有理由 There is someone knocking at the door.It may ________ (be) the postman.如题 someone is knocking at the door.___must be Tom.为什么用he而不用it? There is__(nobody,somebody.anybody,everybody)knocking at the door,Go and see who it is