听力原文：W: Excuse me, Dr. Chandler, do you have a moment? I want W talk about the topic of my paper. M: Of course, what can I do for you, Sienna? W: (19) I want to change the topic of my paper. You know I was writing about Apollo 11, but now I want to write about something else. I've just found something better. M: I'm surprised. On Monday, you were showing me all the pictures of the moon landing you'd found on the Internet. I thought you would do a good job on the Apollo 11 topic. W: (21) Well, yesterday my friend introduced me to her uncle, who was an astronaut at NASA up until a year ago. I'd like to write about him if that's okay. I believe that I can do better if I change my topic. M: Yes, that sounds like it'll be a fascinating paper. Make sure you include some historical facts, though this gentleman's job must have been very interesting, but don't forget the historical context or background. W: I've got some books about the American space program. I'll finish reading them as soon as possible. M: That sounds like a good start. (20) You could talk a little about the European and Russian space programs, too. W: I'll do that. I'll see you next week, Dr. Chandler. We can talk about my further improvement. I'll prepare for it. Thank you, Dr. Chandler! M: Bye, Sienna. I am looking forward to reading your paper. (20)