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Where Are We?
我们在哪里？
Where are we?
我们在哪里？
That was a big question when we first explors our world long ago.
很久以前人们刚开始探索世界的时候这是一个很困难的问题。
The early explorers found that the stars in the sky were good guiding marks.
早期的探索家发现天空中的星星是很好的标记。
Using the stars, they could find out where they were and in which direction they were going.
通过星星，他们能够知道自己在哪里，在往哪个方向前进。
This method worked well at night as long as the weather was good and the stars could be seen.
只要天气晴朗，星星清晰可见，这种方法就很有效。
But it didn't work so well during the rest of the time.
但是其他时间效果就不太好了。
That was a problem.
这是个问题。
Today, the problem has been solved by the Global Postitoning System(GPS).
现在，这个问题已经被全球定位系统（GPS）解决了。
It is like a man-made star.
它就像是人造星星。
We can use it at any time, in any place and in any weather to find out our position.
我们随时随地、在任何天气状况下都能用它找到我们的位置。
It can also be used to study the shape of the earth.
它还可以用来研究地球的形状。
The GPS is a great invention that helps us explore our planet and discover where we are.
全球定位系统是一个很伟大的发明，能够帮助我们探索地球，寻找位置。
