It was found that fire, which appears to destroy, only transmutes: elements are recombined, but each atom that existed before combustion still exists when the process is completed.

人们发现了那似乎在毁灭着万物的火，只不过是使万物变形而已；原素可以重新结合起来，燃烧之前就已存在的每一个原子经过燃烧过程之后，仍然继续存在着。

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Before mixing with the products of combustion, the air is preheated.

空气在与燃烧生成物混合之前要进行预热。

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Increasing the pressure of the fuel mixture in the combustion chamber before ignition helps to increase the power of an engine. This is done by compressing the fuel mixture to a smaller volume.

在点火前增加燃烧室内可燃混合气的压力有助于提高发动机的功率，这是通过把可燃混合气压缩到一个极小的体积来实现的。

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There is technology in the works today that can economically clean coal before combustion and reduce emissions to levels rivaling the emissions of a natural gas fired plant.

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Nitrogen is separated from oxygen before combustion, thereby reducing the volume of exhaust gas and making the exhaust easier to treat by preventing the formation of polluting nitrogen oxides.

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If you were plowing a field in the era before the internal combustion engine, the harness was the only way to get the job done right.

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