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However, when early humans first began to reflect on the nature of things around them, they discovered that they needed an idea of number simply to keep their thoughts in order.

然而，当早期的人类第一次开始反思周围事物的本质，他们发现只是为了让思维保持有序也需要有数字的概念。

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About 10, 000 years ago, modern humans discovered how to make knives out of copper, and around 5, 000 years ago, craftsmen in the Near East began to make them out of bronze.

FORBES: No. 1 The Knife

Physicist (and revolutionary) Max Tegmark likes to say that his grandmother grew up in a different universe, because since the time when she was a child, humans have discovered that the cosmos extends much farther, and obeys vastly different rules, than previously believed.

FORBES: Ten People Who Could Change The World

The H7N9 virus, a form of avian flu not before seen in humans, was discovered in pigeons being sold in the market.

BBC: China culls poultry as bird flu death toll reaches six