Do you know what a satellite is? 你知道什么是人造卫星吗？

　　It is an object made by humans. 它是人类制造的产物。

　　Like the moon, it circles around the Earth. 就像月球一样，它围绕地球旋转。

　　How many satellites are there around the Earth? 围绕地球旋转的人造卫星有多少颗？

　　There are over 5000 satellites. 5000多颗。

　　What do they do in the sky? 它们在天上有什么作用？

　　They observed the Earth for many different purposes. 它们观测地球，有不同的用途。

　　Military satellites watch enemies, non-military satellite watch road conditions, weather changes and so on. 军事人造卫星用于监视敌人，非军事人造卫星用于监视路况，天气变化等等。

　　Are there any humans inside the satellite? 人造卫星里有人吗？

　　No, they're only machines inside satellite. 没有，里面只有机器。

　　The first satellite in the world was Sputnik, and it was only the size of a soccer ball. 世界上第一颗人造卫星叫斯帕特尼克，它只有足球大小。