听力原文：M: Hey, Jane! What's so interesting? W: What? Oh, hi, Tom! I' m reading this fascinating article on the societies of the lee Age during the Pleistocene period. M: The Ice Age? There weren't any societies then—just a hunch of cave people. W: That' s what people used to think. But a new exhibit at the American Museum of Natural History shows that Ice Age people where surprisingly advanced. M: Oh, really? In what ways? W: Well, Ice Age people were the inventors of language, art, and music as we know it. And they didn't live in caves they built their own shelters. M: What did they use to build them? The cold weather would have killed off most of the trees, so they couldn't have used wood. W: In some of the warmer climates they did build houses of wood. In other places they used animal bones and skins or lived in natural stone shelters. M: How did they stay warm? Animal-skin walls don' t sound very sturdy. W: Well, it says here that in the early Ice Age they often faced their homes toward the south to take advantage of the sun— a primitive sort of solar heating. M: Hey, that' s pretty smart. W: Then people in the late Ice Age even insulated their homes by putting heated cobblestones on the floor. M: I guess I spoke too soon. Can I read that magazine article after you' re done? I think I' m going to try to impress my anthropology teacher with my amazing knowledge of Ice Age civilization. W: What a show-off! (20)