In fact, it is converted to folate in the liver by the addition of four hydrogen atoms.

事实上，它在肝脏中与四个氢原子结合后转化成叶酸。

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So we can bring in four hydrogen atoms, which will each contribute another unpaired electron.

我们可以引入4个氢原子，每个贡献一个未配对的电子。

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The challenge is to take a molecule of methane, the main component of natural gas consisting of one carbon atom and four hydrogen atoms, and turn it into something bigger.

天然气的主要成分是甲烷，它含有一个碳原子和四个氢原子，这项转化的关键是把一个甲烷分子变大。

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So we can bring in four hydrogen atoms, which will each contribute another unpaired electron.

我们可以引入4个氢原子，每个贡献一个未配对的电子。

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Natural gas contains only one carbon and four hydrogen atoms per molecule, making it the cleanest of fossil fuels.

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Natural gas is mostly methane, which has four hydrogen atoms for every carbon atom the maximum that is physically possible for a hydrocarbon.

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The carbon combines with the hydrogen in water to make carbon monoxide and hydrogen gas--the old "town gas"--but then the catalyst prompts a rejiggering of the atoms into methane (one carbon atom attached to four hydrogen atoms).

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