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- The solar system was formed 4.5 billion years ago. 太阳系是四十五亿年前形成的。
- It has a half-life of about 41/2 billion years. 它的半衰期大约为45亿年。
- A star can persist like this for 10 billion years. 这样的恒星可以持续一百亿年以上。
- 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。
- 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。
- The stars must have formed around 10 billion years ago. 星星一定是在大约一百亿年前形成的。
- Earth does not wish to recreate the past 24 billion years of falls again. 地球并不希望再次重复过去240亿年间所经历的下降。
- But people have been eating according to flavor for upwards of a billion years. 但是人们已经根据滋味来吃东西吃了十亿年以上了。
- The lava flows are hotter than anything seen on Earth in two billion years. 四处流淌的熔浆比地球在近二十亿年间的任何东西都要热。
- Several billion years passed.Then a Little Bang birthed our solar system. 几十亿年过去之后，我们的太阳系诞生于小爆炸。
- About three billion years ago,life on our planet began in the deep blue seas. 大约有三十亿年以前，在我们的星球上，生命从蓝色的海洋深处开始。
- At room temperature, the odds of that happening are once in a billion years. 在室温条件下，发生那种情况的机会十亿年内只有一次。
- Subarctic temperatures will force us underground for a billion years. |到那个时候我们就要在地下住好几十亿年呢！
- Through about two billion years, the development of plants and animals on our earth have been going on. 贯穿大约二十亿年的漫长历史，我们地球上各种植物和动物的进化一直在进行。
- Your single-celled ilk, microscopic bacteria and algae, have ruled the primordial seas for almost 3 billion years. 你的单细胞同类----非常小的细菌与海藻，已经统治这片原始海洋几近30亿年之久。
- The best stggestion 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。
- 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。
- 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。
- This is about ten billion years, after which the Sun will swell up and engulf the Earth. 这个限期大约是100亿年，以后太阳将会膨胀并吞没地球。
- As a result, major lunar eruptions of basalt, the most common volcanic rock, ceased nearly three billion years ago. 因此在约30亿年前，月球上大多数的玄武岩岩浆（最常见的火山岩）喷发就已经停止了。
