托福TPO71综合写作阅读原文+听力原文及音频下载

托福TPO71综合写作阅读原文+听力原文及音频下载

阅读部分

The fossil record shows that members of the group of dinosaurs known as lambeosaurs had large bony crests on top of their heads. The shape of the crests varied from species to species, but all lambeosaur crests contained extended hollow passages. No one really knows exactly what function the crests served, but scientists have offered several theories.

Sense of smell

One theory holds that the primary purpose of the crests was to improve the dinosaurs' sense of smell. Examination of the fossils has suggested that the crests contained many blood vessels. The nose bones of modern animals with a highly developed sense of smell have a similar inner structure characterized by a high density of blood vessels Thus, it is reasonable to conclude that the crests were primarily used to enhance the sense of smell.

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听力部分：

Now, listen to part of a lecture on the topic you just read about.

I think that it's still not clear what the real function of the lambeosaur crest was. There are serious problems with each of the theories you just read about. First, the idea that the crest improve the lambeosaur source sense of smell is not supported by the structure of lambeosaur or brains in animals with a strong sense of smell. The brain area next to the organ of smell tends to be well developed. That's because the brain area contains a lot of nerves that process the Information from the organ of smell. However, from fossils of lambeosaur source skulls, it seems the brain cavity next to the crest was small and underdeveloped. So it hardly seems likely that the crest was used to improve the sense of smell.

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