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.

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。