Snow covers the road on cold days.
天冷下雪，路面就白白一片。
People spread salt on the snow.
人们把盐撒在雪上。
Salt makes ice melt at a lower temperature.
盐能让冰在更低的温度下融化。
Pure ice melts at zero degrees.
纯水做的冰，零度就会化。
With salt, it needs a colder day to freeze.
加了盐，天更冷才会重新结冰。
So the road stays clear and safe.
路面化得快，走路开车都安全。
That is why salt comes out in winter.
所以一到冬天，盐就派上了用场。
