A: Good afternoon. I am the front desk. Do you need my help? B: Yes. I left after 4 hours but came back to find the room not clean. A: I'm very sorry. I'll let the room service staff come at once. What 's your room number? B: Room 311. How long will it take? A: About 20 minutes. B: Well, I can only wait. A: Let 's go to the cafeteria for a while. Will we get you a drink for free? B: Okay, but I hope I'll be able to sleep soon. A: No problem. I apologize for the inconvenience.