根据我的记忆，水往复地变化，从湖泊和海洋里的水变成水蒸气，然后当它以雨或雪——也就是降水的形式落下时又变成水。

From what I remember, water changes back and forth from water in lakes and oceans to vapor, and then back to water again when it falls as rain or snow, as precipitation.

youdao

太阳照射下，水变成水蒸气。

The sun shines and the water becomes vapour.

youdao

当水变成水蒸气时，我们把这个过程叫做蒸发。

When water changes to water vapour, we say it evaporates.

youdao