云中的小水滴不断地相互碰撞，逐渐变、变重，最后变成雨落到地面。

When the droplets in the clouds collide, they become too big and heavy, they fall to earth again as rain.

youdao

云中的小水滴不断地相互碰撞，逐渐变、变重，最后变成雨落到地面。

When the droplets in the clouds collide, they become too big and heavy, they fall to earth again as rain.

youdao