听力原文：W: Hey, Joe. What's all this talk about a benefit walkathon this weekend? M: Don't you know? Most of the residents in Parker Hall are going to try to walk the seven miles from the Engineering Library, across campus, and down to City Hall in an effort to raise money for the new children's hospital. W: Sounds like a good ideal But I don't understand where the money comes from. M: Well, a few days before the walkathon, each participant goes around asking people to pledge a certain amount of money for each mile that he or she expects to walk in the event. Then after the walkathon is over, the participants go back to those same people, collect the money pledged, and send it to the hospital. W: So you mean if you pledge, say, a dollar a mile and you walk five miles, then you get five dollars. M: That's fight. Of course most of my friends aren't such big spenders. The biggest pledge I've gotten so far is 25 cents a mile. W: And how many people have made pledges for you? M: Eleven so far. Say, how about making it a dozen? W: Sure. If you'll do the same for me. The walkathon sounds like the perfect opportunity for me to break in my new pair of sports shoes. (23)