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| Rockets in the Sky | |
| 摘 要： | What is the sky? Where is it? How high is it? What lies above the sky? I am sure that you have asked questions like these. They are very difficult to answer, aren't they?Perhaps we can answer some of these questions now. What is the sky? It is vast space. In the sky there is the sun, the moon, and all the stars.Scientists have always wanted to know more about space. They use telescopes to obtain information. But this |
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