___________--someone is singing upstairs It must be Maria.

___________--someone is singing upstairs It must be Maria. Someone is singing now.Who （）it be?A.must B.should C.can D.w who is singing next room?is it Maria?no ,it ?be her.she is s who is singing in the next room?_____must be Maria.空格应该填It还是 Listen!Someone is singing next door.Who ( ) it be?填can还是may? who is singing?it must be susan.为什么是用it -Who is singing in the next room.-_ must be Marie A.It B.She Listen!someone is singing there .it ________ beautiful. There is someone in the room.It must be my brother My watch is m___.Someone must have stole it Someone is singing in next room.Please go and see who it is. Someone must hear her singing the song.改被动语态.