听力原文：M: Are you the head resident? W: Yes. M: I'm Bill Miller. I'm here because I want to change roommates. W: Really? That surprises me. I thought that you and David were good friends. M: We were. You see, we knew each other before. We are from the same home town, but it looks like we had different reasons for coming to col- lege. W: How so? M: Well, David is really into having fun, which is great. But he has so many people in our room all the time that 1 can't study. And the stereo is on constantly. W: Have you talked to him about it? M: Yes, but he just doesn't take me seriously. W: I see. M: Miss Todd, I have to study. I'm on scholarship. David isn't. W: Okay. Here's what we can do. Let me talk to David, and then you see how it goes. Just one week. What do the speakers mainly discuss?