听力原文：W: We' d better be looking for sales on down jackets and thermos underwear. It' s

M: Well, you didn't expect it to be warm, did you？

W: Of course not, but I heard the national weather service's prediction for the next 90 days. They said it' s supposed to be much colder weather than usual.

M: Yeah, maybe. Personally, I think those long-range forecasts are useless.

W: Not as useless as you think.

M: Oh, come on, when you' re talking about what' s going to happen three months later, you might as well just pick a forecast out of our hat.

W: Well, you are partly right. They area' t very good at the amount of water falling on the earth. But they are much better for temperatures especially for this time of the year.

M: Really？ So I should take them seriously about the cold but not count too much on a lot of extra snow？

W: Exactly.

M: But what did you say about this time of the year？ Do some seasons really give them more problems in making forecasts？

W: Autumn is the worst; apparently weather patterns change so much then. Just think how variable our weather has been the last three months.

M: Come to think of it, that' s true. It probably would have been hard to predict all those chan ges back in the summer. You know, you' re beginning to convince me there is more to fore casting than I thought. How come you know so much about it？

W: I get my information from an expert--my sister.

(23)

A．The foundation.

B．The reliability.

C．The history.

D．The source.