所以要是你获得了放射性元素的正确类型矿石后，等上数十亿年（甚至数万亿年）就能获得地下隐藏着的大量氦！

So if you get an ore of the right type of radioactive element, and you wait millions and millions (or even billions) of years, you make a giant underground store of helium !

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这些中英对照的文章主要是测试你的理解能力。所以，中文翻译设了隐藏。你必须读完文章后，用英文回复，就可以看到中文的翻译了。

This is to test your understanding of the articles. Chinese words are hidden so that you learn to read the English passage, then reply to see the translations.

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