fáng jiān mén kǒu de qǐng wù dǎ rǎo dēng liàng zhe, kè fáng fú wù tōng cháng bú huì jìn fáng jiān

房间门口的请勿打扰灯亮着，客房服务通常不会进房间。

If the 'Do Not Disturb' light is on at the door, housekeeping usually won't enter the room.