| 1. | 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。 |
| 2. | Their ancestors have been eating according to flavor for upwards of a billion years .
他们的祖先已经根据滋味来吃东西吃了十亿年以上了。 |
| 3. | Now that curtain has risen and men can look back to a past of scores and hundreds of millions of years .
帘幕已揭开，人们可以回溯几十亿年之久的过去了。 |
| 4. | The best suggestion is that jupiter is still contracting gravitationally despite its age of several billion years .
最好的说明是：木星尽管已有几十亿年的历史，但由于引力作用，它仍在收缩。 |
| 5. | Practically every atom had its origin in the tiny violence of a radioactive disintegration some time within the past few billion years .
实际上每个原子都来源于过去几十亿年中某一时刻放射性分裂的微小激变。 |
| 6. | The organisms living between 3 and 1 billion years ago were not as versatile as modern species, probably due to energy limitation .
生活在过去二十亿年之间的有机体可能由于能量的限制，不如现代物种这样五花八门。 |
| 7. | Modern astronomers, gazing at stars and galaxies far away from the earth, can reconstruct what occurred only minutes after the creation of the universe, billions of years ago .
现代天文学家凝望着远离地球的星体，星系，从而领悟出数十亿年之前宇宙诞生后的短短几分钟内发生了哪些现象。 |
| 8. | Our solar system was formed 4 . 6 billion years ago
我们的太阳系被形成了4 . 6十亿年前。 |
| 9. | Then 65 million years ago they suddenly disappeared disappeared
然而六百五十亿年前他们突然消失了。 |
| 10. | Billions of years ago the universe was too hot for life to exist
数十亿年前，宇宙太热，不适合生命存在。 |
