蓓蓓看着天空中一朵朵象棉花团一样的云彩,问爸爸:天空为什么会有云,会下雨? 爸爸觉得蓓蓓提的问题很有趣,就耐心地给她讲了起来。爸爸从人们最熟悉的水讲起。在整个地球上,江、河、湖、海以至一切土壤和所有的动植物每时每刻都在把水分蒸发到空中,变成看不见的水汽,水汽又凝结成我们所见到的云、雾、雨、雪,降到地面。或渗入土壤,或流入江河,汇入大海,接着又是蒸发……就这样不断地循环,水分就象一个活泼的小姑娘,在循环过程中不断改变着自己的状态。 Bei Bei looked at the sky like blossoming like cotton clouds, and asked Dad: why the sky there will be clouds, it will rain? Bei Bei Dai asked the question is very interesting, patiently told her to speak up. Dad speaks from the most familiar water. Throughout the earth, rivers, rivers, lakes, seas, and all the soil and all the animals and plants, all the time, evaporate the water into the air and turn it into an invisible water vapor that condenses into the clouds we see. Fog, rain, snow, falling to the ground. Or infiltrate the soil, or into the rivers, into the sea, and then evaporated again ... so constantly circulating, water is like a lively little girl, constantly changing his state during the cycle.