Many people know what the water cycle is, but how about the rock cycle? 许多人都知道水循环，那岩石循环呢？

　　Did you know that rocks also have a cycle? 你知道岩石也有循环吗？

　　The rock cycle explains how rocks get old, melt and become rocks again. 岩石循环解释了岩石是怎么老化、熔化并再次成为岩石的。

　　Yes, the rocks become old, too. 是的，岩石也会老化。

　　So, what makes rocks get old? 那么，什么使得岩石老化的？

　　Volcanoes, wind, rain, sunlight and other natural events change rocks. 火山爆发、风、雨、阳光和其他自然事件都会改变岩石。

　　What is the most important activity for the rock cycle? Volcanic activity. 对岩石循环作用最大的活动是什么？火山爆发。

　　Without volcanic eruptions, there would be no rock cycle. 没有火山爆发，就不会有岩石循环。

　　However, other natural events are also important to change rocks from one type to another type. 但是，其他的自然事件对改变岩石的类型也很重要。