为控制害虫，人们持续且不计后果地使用人工合成化学品，对农作物和人类健康造成危害，事实证明会产生相反的效果。

The continuous and reckless use of synthetic chemicals for the control of pests which pose a threat to agricultural crops and human health is proving to be counter-productive.

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—深色染发剂：已被证明含有致癌化学物质煤焦油。

Dark hair dyes: They are known to contain coal tar, a carcinogenic chemical.

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也就是，从中我们将证明，混合物的化学势，永远比纯净物的低。

Which is that, from what we're going to prove, is that the chemical potential in the mixture is always less than for the pure substance.

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