Sometimes the sky is full of white clouds. But sometimes clouds look black. Where does the colour come from?

Clouds are made¹ of water or ice. But the drops of water in the clouds are not red or orange. The sun makes the colours in the clouds. Sunshine² changes colour as³ it goes through the drops of water in the clouds.

Clouds look dark⁴ because they are so thick. Lots of drops of water make a cloud. Very little sunshine can go through. Dust⁵ also makes clouds dark. Dust from the ground⁶ is blown into the sky. and becomes part⁷ of the clouds.

The colours of the clouds tell about the wether.

有时天空布满了白云，可是有时云看起来是黑的。这些颜色是从哪里来的呢？

云是由水和冰组成的。可是云中的水滴冰不是红色或橘黄的。太阳使云有了颜色。当阳光穿过云中的水滴是改变了颜色。

云看起来暗是因为云层太厚了。许多水滴组成了云，很少的阳光能穿透云层。尘埃也能是云变暗。地面上的尘埃被吹到空中时，它就成了云的一部分。通过云彩的颜色能预报天气。