听力原文：M: Mary, (19)you want to talk about your second essay, right? W: Yes, Dr. Richardson. I just need your comments on what I'm planning to do. (19)I'm doing the essay on the differences between TV news programs at different hours of the day. M: How many times slots are you planning to consider? W: Well, I think I'd look at all of them. That'd be five slots. The breakfast news, midmorning news. midday news. mid-afternoon news and evening news. M: That's rather a lot. And you'd have too much to consider. (20)Why don't you just do two. Say the midmorning and then evening news. That should give you two contrasting approaches with two main audience compositions. W: OK, just two then. M: Yes, I think that would be much better. Now how many actual programs do you plan to work with? W: What do you think of analyzing a whole week's news programs? M: Well, that depends on how much of each program, if you concentrate on one particular type of news item, say the sports news or local items, it might be alright. W: Yes. that would be a good idea. (21)I won't make a decision before I collect a sample of programs over a whole week. I'll look at them and see what items appear throughout the week. M: Yes, that's a sound approach. (22)Now we’re getting close to the deadline. Can you finish it in time? W: Yes, I think so. I've completed the reading and I know what my basic approach is, so it's really just a matter of pulling it all together now. M: Fine, Mary. I'll look forward to reading it. (23)