【正确答案】 D

【答案解析】[解析] 14-16
W: Hey Joe, what is all this talk about the benefit walkathon this weekend?
M: Don't you know? Most of the residents in Packer Hall are going to try to walk the seven miles from the Engineering Library across campus and down to City Hail in an effort to raise money for the new children's hospital.
W: Sounds like a good idea. 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 just 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 in to the hospital.
W: So you mean if someone pledges, say, a dollar a mile, and you walk five miles you get five dollars.
M: That's right. Of course, most of my friends aren't such big spenders.The biggest pledge rve got so far is twenty-five cents a mile.
W: And how many people've made pledges for you?
M: Eleven so far. Say, how about making it even a dozen?
W: Sure, if you do the same for me. The wafkathon sounds like a perfect opportunity for me to break in my new pair of sport shoes.