水在自然界是循环运动的: 江、河、湖、海、地面上的水,被太阳晒热,不断地蒸发,变成水蒸气飞散到空中。水蒸气在空中受冷变成云,云随风飘动,变成雨、雪等落下来。 降落在地面的雨水和融化了的雪水(或雪),有的又变成水蒸气飞散到空中去了;有的流入江、河、湖,有的渗进地里成为地下水,部分地下水又会流出地面形成泉水,流入江、河、湖,日夜不停地流人海洋。 水在海洋、天空和陆地之间的循 Water circulates in nature: water in rivers, lakes, seas and on the ground is heated by the sun and evaporates continuously into water vapor. Water vapor in the air by the cold into clouds, clouds wind fluttering into rain, snow and other fall. Some rainwater that has landed on the ground and melted snow water (or snow), some of them turn into water vapor and scatter into the air; some flow into rivers, rivers and lakes, and some seep into the ground to become groundwater. Some groundwater Will flow out of the ground to form springs, flowing into the river, river, lake, day and night constantly flowing into the ocean. The water circulates between the sea, the sky and the land