who is singing in the next room?_____must be Maria.空格应该填It还是

who is singing in the next room?_____must be Maria.空格应该填It还是 who is singing next room?is it Maria?no ,it ?be her.she is s -Who is singing in the next room.-_ must be Marie A.It B.She Who () in the next room.填is singing 还是sings 语法说明 原题没有表时态的词语 WHO's singing in the next room?is that ann it___ be her .she Listen!Someone is singing next door.Who ( ) it be?填can还是may? who is singing in the next room 为什么who 后面要跟 is singing? helen is singing in the next room .-It--be helen.she has gon Iisten!Helen is singing in the next room.It ( ) be Helen.She Listen!Who is singing in the next room?这里为什么要用singing Someone is singing in next room.Please go and see who it is. who is singing in the room?