The heat from the sun turns the water to the steam.Then the steam flow up to the sky and turns to the cloud.When it rains,little water drops drop from the sky and these water drops become little river...
是因为太阳的照射,使水变成了水蒸汽.水蒸汽上升到空中变成了云.下雨时,许许多多的小水珠从空中下降