听力原文：M: I'm so tired, I can't see straight. W: You've been tired a lot lately, haven't you? M: Well, for the last few weeks, I have had to stay up most of the nights to observe star configurations for a project for my astronomy class. It's awful! No matter at what time I go to bed, I always wake up at 6 am. That's the time I usually get up. W: Your biological rhythms probably haven't been adjusted to your new schedule. I've read that some people have a lot of trouble when their sleep rhythm is so interrupted. Even sleeping pills don't help them. M: I know. In fact I've heard there are now several special treatment centers for sleep disorders across the country. Some people sleep too little. Some people sleep too much. Some walk in their sleep. W: I'd like to find out how they treat problems like that. Maybe you should go to one of those centers. M: Not me. After next week, my project will be finished and I'll go back to my regular hours. Now I know for sure that I don't want to be an astronomer. (20)