听力原文：(Woman—Susan Man—David) W: What is so interesting in that book, David? M: Oh, Susan, it's a book about the changes in weather. W: We certainly are having different weather this year, aren't we? M: That's why I borrowed this book from the library. I wanted to read about differences in climate. W: Does the book talk about cold weather like we've been having? M: As a matter of fact, it does. It tells how weather seems to come in cycles. There will be periods of very cold winters and very hot summers. W: Well, we've had both this year, haven't we? M: Yes, and according to the book, that type of weather will last for several years. W: Then what happens? Does it just continue to get colder and hotter? M: No, that was what I was afraid of, but the book says that after the very cold/very hot cycle is over, there will be a time of moderate weather. W: What do you mean by 'moderate'? M: The book says that the weather will be cold in the winter but not too cold. In the summer, the temperature will not be so high as it was this last summer. W: Will it last for several years? M: It seems that it will. It's a cycle, just like we're having now. Then it will go back to the very cold and very hot. W: I'll look forward to the moderate years, then. M: Me, too! (20)