听力原文：M: Amy, are you interested in joining us for the party this weekend? W: I'd love to. (19)But I have tutoring then. M: Tutoring? I can hardly imagine that you need a help with a class. W: (19) I mean I'm tutoring someone else, I go downtown to tutor a few students at the high school. M: I find that hard to believe. And what subject do you tutor, math or something else? W: Right. You see, the city is trying to raise the standards for its math classes. (20)The problem is, a lot of the kids are far behind when they get to junior high school. M: Yeah, I have read such report in the newspaper. But does the time schedule conflict with your own classes? W: (21)I only have three students for forty minutes each weekend, Most of the tutors there are students at the university, so our classes aren't over there. And we are volunteers, so the program doesn't cost a lot and the city education department likes us. M: Can you afford to take that much time away from your own studying? W: Some weeks is kind of hard especially when the examination is approaching. But anyway I may as well get used to teaching easy materials to the students, so as to get the practical experience. M: And it must be nice to help people. W: Definitely, Forty minutes a week isn’t much time, (22)but all the three of my students have improved in the months we’ve worked together, It’s really inspiring. (23)