听力原文：M: We're having a debate on advertising Thursday evening and I have to take part. W: That's interesting. I should like to hear what people think about advertising. M: [19] What's there to say? We must have advertising, mustn't we? W: Why? M: Well, [19] we wouldn't know what there was to buy if we didn't have advertisements. W: Yes, that's true up to a point. Advertisements provide information that we need. If someone has produced a new article, naturally, the seller wants to tell us about it. M: Yes. And the advertisements tell us which product is the best. W: Do they? I don't think so. Every manufacturer says that his product is the best or at least tries to give the impression. [20] Only one can be the best, so the others are misleading, aren't they? M: Well, in a way, I suppose. But we don't have to believe them, do we? W: Are you saying that advertisements aren't effective? I don't think that intelligent businessmen will spend millions of dollars on advertising if nobody believes the advertisements, do you? M: Perhaps not. But after all, it's their money that they are spending. W: Is it? I think not. The cost of advertising is added to the price of the article. [21] You and I and all the other people who buy the article pay for the advertising. M: Well, I suppose we get something for our money… some information. W: Yes, [20] but don't forget it's often misleading information, and sometimes harmful. M: Harmful? W: What about advertisements designed to persuade young people to smoke cigarettes? Wouldn't you say they are harmful? M: You've given me a lot to think about. I'm quite looking forward to the debate now. (20)