| 1. | It has a half-life of about 41/2 billion years .
它的半衰期大约为45亿年。
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| 2. | Pennsylvania sits on 35 billion tons of coal .
宾州煤的蕴藏量为三百五十亿吨。
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| 3. | But these imports came to nearly 127 billion dollars .
但是，这些进口商品的价值总额却接近1270亿美元。
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| 4. | At some time more than five billion years ago the universe started .
在50亿年前的某个时候，宇宙开始形成。
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| 5. | The universe as a whole contains billions of comparable galaxies .
整个宇宙，包含亿万个可以比拟的银河系。
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| 6. | The sun has been emitting energy at this rate for billions of years .
太阳以这样的强度辐射已有10亿年之久。
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| 7. | A bank had billions of dollars in clients' trust funds to invest .
银行吸引了几十亿美元的客户信托金供投资之用。
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| 8. | The savings due to increased health would be about 2 billion annually .
由于增进了健康，每年节约为20亿美元左右。
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| 9. | The youngest rocks found on the moon are 3 billion years old .
在月球上发现的地质年代最晚的岩石已有30亿年历史了。
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| 10. | As a slowly contracting dwarf the star may remain luminous for billions of years .
收缩较慢的白矮星仍会发光几十亿年。
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