【英语时差8,16】山洞人-下

（单词翻译）

There are several reasons. First, much evidence of prehistoric¹ civilization is found in caves because the natural shelter helps preserve artifacts. The earliest cave dwellers² date to the Paleolithic period, around 2.5 million years ago, and evidence suggests that these ancient nomads³ used caves as temporary shelters during their seasonal⁴ wanderings. The caves often lay on valley slopes and provided excellent views of animal migration⁵ routes. But there is no evidence that Stone Age peoples set up shop in caves for very long. Even Neanderthals, who lived in relatively⁶ cold regions of ancient Europe, used caves only for temporary shelter. Our more immediate⁷ ancestors did, of course, eventually move indoors. But permanent dwellings⁸ came about only with the invention of agriculture and animal husbandry. Before those world-changing inventions, prehistoric people were forced to follow their food away from the warmth and shelter of the cave.