Oil is refined to remove naturally occurring impurities.

油经过提炼去除天然生成的杂质。

《柯林斯英汉双解大词典》

At present, we can make efficient use of only naturally occurring hot water or steam deposits.

目前，我们只能有效地利用自然产生的热水或蒸汽沉积物。

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Apart from that, the process of heating up naturally occurring materials to transform them is the same.

除此之外，将天然生成的物质加热转化的过程也是如此。

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Brown rice is the naturally occurring form of the grain.

VOA: standard.2010.06.25

Insulin is a naturally occurring hormone, it's a protein hormone that circulates in all of our bodies and regulates glucose metabolism.

胰岛素是人体自身产生的一种激素,它是一种蛋白质激素,遍布全身,并调节糖代谢

耶鲁公开课 - 生物医学工程探索课程节选

So, that was a naturally occurring attenuated virus that could be produced into a vaccine that didn't cause the disease.

因为天花病毒存在天然的衰减病毒,这种衰减病毒可以用来,直接生产不致病的疫苗

耶鲁公开课 - 生物医学工程探索课程节选

Zovant is an artificially created version of a naturally occurring protein called Activated Protein C.

BBC: Breakthrough on killer infection

In fact, standards for NORM (naturally occurring radioactive material) have been observed for years.

FORBES: Don't Be Swayed By Faucets On Fire And Other Anti-Fracking Propaganda

The European Union is particularly concerned by a naturally occurring oestrogen known as oestradiol.

BBC: How safe is hormone-treated meat?