钢是铁与碳的合金，焦煤便是熔炼过程中碳的来源。

Steel is an alloy of iron and carbon. Coking coal is a source of carbon in the smelting process.

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砍伐森林建牧场，以及过度放牧导致土壤中碳含量的净流失等因素都会产生大量的二氧化碳。

Livestock farming also accounts for a lot of carbon dioxide, mostly from forests being cut down for pasture, or when overgrazing and the resulting soil erosion causes a net loss of carbon from soils.

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而多数行星模型均假设它们和我们太阳系的类地行星相似，即在大气中碳含量是氧含量的一半左右。

Most models of planets assume that they are similar to the terrestrial planets in our own Solar System, with about half as much carbon as oxygen in the atmosphere.

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So either a potassium cyanide or sodium cyanide, these are used in synthesis in terms of making carbon-carbon bonds.

因此无论是氰化钾还是氰化钠，都被用来在合成过程中,制造碳碳键。

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And because, of course, we have this carbon here what you end up doing is adding a carbon to your molecule.

因为，当然，我们这里有一个碳,接下来需要做的就是在你的分子中再加上一个碳。

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Fat has twice the calories per unit weight that protein or carbohydrate sugar has, as a consequence, has the greatest survival value.

单位重量中脂肪的热量含量,是蛋白质和碳水化合物的两倍,因此,脂肪才是最能维持生存的物质

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