可是这一切必定有过第一次出现的时候。

　　Someone must have made the discovery.

　　这必定是某个人发明的。

　　Isn't it an amazing thought that, one day, a prehistoric man – or a woman

　　有一天一名史前时期的男人或女人

　　– must have realized that meat from wild animals was easier to chew if it was first held over a fire and roasted?

　　一定意识到野兽的肉放在火上烤一烤，那么这肉也许就会好咬一些。

　　And that one day someone discovered how to make fire?

　　这是不是一个神奇的想法呢？ 有一天一个人发现如何生火？

　　Do you realize what that actually means? Can you do it?

　　你知道这意味着什么吗？你会做吗？

　　Not with matches, because they didn't exist.

　　没有火柴，因为他们不存在。

　　But by rubbing two sticks together until they become so hot that in the end they catch fire.

　　但你不断摩擦两根棍棒，使它们变得越来越热并最终燃烧起来。

　　Have a go and then you'll see how hard it is!

　　你来试一试就明白这有多难了！

　　Tools must have been invented by someone too.

　　工具也是有人发明的。

　　The earliest ones were probably just sticks and stones.

　　最早的工具大概就是树枝和石头。

　　But soon stones were being shaped and sharpened.

　　但不久人们就把这石头打造成尖锤。

　　We have found lots of these shaped stones in the ground.

　　我们在地下已经找到了许多这样打造的石头。

　　And because of these stone tools we call this time the Stone Age.

　　因为这些工具都是用石头做的，所以我们称这个时期为石器时期。