In the heat of the sun, water evaporates from seas, rivers and lakes. As water vapour rises, clouds form in the air. When the clouds rise high, they get cool. Finally they become drops of water. When they are heavy enough, they fall to the earth as rain.
在太陽的照射下，水從大海、河流和湖泊上蒸發(fā)。當(dāng)水蒸氣上升時，云就在空中形成了。當(dāng)云升高后，就變涼了，最后變成了一滴滴的水。當(dāng)水變得足夠重時，就作為雨水落到地面上。
