This is room.要选哪个

This is room.要选哪个 teachers' room;the teachers'room.this is ()room,这里应该选哪个? Look,this is( )empty room A\a B\anC\ D\the选哪个 This is a room “Whose room is this? This is（）room this is( )room. This room is ___that one. What is this room like This is p_____of her room. this is a living room this room is( )that one.选错的 为什么?