这种维生素在几乎只存在于动物制品中，如牛奶、鸡蛋和奶酪。

This vitamin is found almost exclusively in animal products, including milk, eggs and cheese.

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素食者如不食用大量的牛奶和鸡蛋，会因缺乏维生素B12患上恶性贫血症。

Vegetarians are particularly subject to pernicious anemia (results from deficiency of vitamin B12) unless they eat generous amounts of milk and eggs.

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牛奶是蛋白质、维生素d和钙的最佳来源，它们能生成肌肉，保持骨骼健壮。

Milk is an excellent source of lean protein, vitamin d, and calcium that can help build your muscles and keep your bones strong.

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