A、It’s another way to lose weight. B、It’s very cheap. C、It’s not so crowded. D、It’s nearby. D女士说娱乐中心离她的住处很近，故选D。

W: Hi, I understand that there are aerobic classes for students and I’m wondering if you have the schedule for the upcoming sessions?
M: Sorry, I don’t have a paper copy of it on hand right now, but I can tell you the schedule if you’re interested.
W: Sure, I would really appreciate that.
M: Well, the school provides free aerobic classes weekdays from twelve to one. There’s another from five to six in the evenings.
W: Do I have to register before I join?
M: No, you don’t have to. It’s open to all students but you’ll need to bring your student ID card. In fact, ’it’s organized by the Student Union, free of charge, as they like to say, "promote and encourage a healthy lifestyle for students".
W: Is it going to be very crowded like last year? Do you think there will be enough room for students to move around freely?
M: Sure, it’s held at the Elizabeth Hall and we can accommodate up to 100 students. But the average turnout is around 40 so there’s plenty of room.
W: Sounds great. I have always wanted to do aerobics but I wouldn’t want to be doing it if it’s going to be jam-packed like disco or something. And, it being free is another nice part.
M: Well, in that case you’ll have to make full use of this opportunity then. Oh, I forgot to mention that you could also attend the aerobic classes at the downtown recreation center for nothing if you produce the student ID.
W: Sounds great. It is very close to where I live. Thank you so much!
19. What does the woman want to do first?
20. Why does the Student Union hold this activity?
21. What is the woman’s concern about joining aerobics, based on her experience?
22. Why is the woman so happy that she can go to the recreation center?