为了养活地球上70亿人，今天的大多数农民只种植或养殖易于大量生产的植物和动物。

To feed the seven billion people on Earth, most farmers today are growing only species of plants and farming only species of animals that are easy to produce in large numbers.

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后来，一些人发现把动物的油脂或脂肪擦到皮革的内层，可以帮助皮革变柔软。

Later, someone discovered that animal grease or fat rubbed into the inner side helped the leather to become soft.

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挑选一本书，一个人，动物或物品，只做动作让其他人猜出你动作的谜底。

Pick a book, person, animal or object and using only actions get the others to guess what you are.

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