Who is singing in the classroom

A:who is singing in the classroom listen,who is singing in the classroom? Who is singing in the classroom?I want to know 31.—Who is singing in the classroom  — must be Susan .A Who is in the classroom who is singing in the room? Who is the girl in the classroom? who _______ in the classroom?Kitty is. who is singing in the next room 为什么who 后面要跟 is singing? Susan is singing in the classroom.对singing提问 Frank never see ---who is singing and dancing in the gym now? They are singing in the classroom.对"are singing"提问