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我现在复习T,今天听听力突然发现一片听力和我19号考试那天碰到的一篇RC非常像，基本上是一样的，只不过G里面分成了三段，然后每个理论给了一个名字，更长，现在贴上来，有功夫的就看看吧！希望能有点帮助！ We are going to talk today about the moon, our moon. First of all, the earth's moon is unusual. Why? It's larger than other moons or satellites in the solar system, in relation to its planet. Its diameter is more than a quarter that of the earth. And if you compare the earth and the moon in terms of substance, you find the moon isn't much like the earth. For example, the earth has a significant iron core, but the moon contains very little heavy materials like iron. That's why its density is much lower than that of the earth.
Now one time it was believed that the moon and the earth were formed at the same time from the same material. But then wouldn't the moon have as much iron as the earth? Another theory is that the moon was formed elsewhere in the solar system, and then it was captured, sort of speak, by earth. But study shows that the young earth would not have had enough gravitational force to stop a body the size of a moon from traveling through the solar system and pull it into orbit.
The newest theory is called the big splash theory Here, the new young earth was hit by another big planet. Most of the colliding planet entered the earth and became part of it. But the huge impact created a vapor that shed out into space and eventually condensed as the moon. Because this material came mostly from the earth surface crust, not the iron core, the moon contains almost no iron. Well, as plausible as it sounds, it' s only a theory, and we can't be sure that this is what really happened, that this is how the moon originated. Plenty of research remained to be done.
考试时候的重点问的是最后一段，形成过程的描述是一样的！ | 
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发表于 2007-7-25 22:26:00
