水循环是一个常见的、浅显的自然现象。水蒸发后,水蒸气由风抬升,飞过高山,然而冷却、压缩、降水、流回,再进入另一个循环。地球每转动24小时就有14万亿吨的水被抬升到大气之中,其中约20%会降回我们生活的陆地。位置、时机和温度是由我们现在开始了解的多个因 Water cycle is a common, simple natural phenomenon. After the water evaporates, the water vapor is lifted by the wind, flying over the mountains, while cooling, compressing, precipitating, flowing back and entering another cycle. About 14 trillion tons of water are lifted to the atmosphere every 24 hours of Earth’s rotation, and about 20% of the earth’s surface will drop back to where we live. Location, timing and temperature are many factors that we are beginning to understand