油经过提炼去除天然生成的杂质。

Oil is refined to remove naturally occurring impurities.

《柯林斯英汉双解大词典》

一些人认为这些人长寿应归功于他们饮用的一种明显不含杂质的天然矿泉水。

Some people have attributed this longevity to their consumption of a natural mineral water, which is remarkably free from impurities.

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一些专家认为这些人长寿应归功于他们饮用的明显不含杂质的天然矿物质水。

Some have attributed this longevity to their consumption of a natural mineral water, which is remarkably free from impurities.

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