听力原文：M: Congratulations on breaking the records at the recent Olympics, Miss Green ! W: Thank you, Mr Parker. M: Oh, look at those trophies! You became a swimming star at the age of fifteen, didn' t you? W: Yeah, you' re fight. M: Could you tell me something about your plans for the future? W: To tell you the truth, I' m going to give up swimming from now on. M: I beg your pardon? W: I mean I' d rather not swim at all. I' m too old to. . . M: Excuse me, if I'm not wrong, you're only twenty now. Is it too old at twenty ? W: Yes, too old for a swimmer. If I swim in an international competition, I' ll hardly be able to win. M: But. . er. . . don' t you enjoy swimming? W: Certainly, and I enjoy visiting other countries, and the Olympics are very exciting. However, I missed more important things. I had to work very hard at swimming. There was training before school, after school, and at weekends. While other girls were growing up, I was swimming, swimming. But life isn' t merely swimming, is it? When did Miss Green become a swimming star?