A rainbow is an arch of different colours that you can sometimes see in the sky after rain. It is, in fact, made up of water drops that get together in the sunlight and, through the refraction and the reflection of the light, form the coloured bow.
One day last summer it rained heavily in the afternoon. After the rain, there appeared a spectacular rainbow slanting up in the sky. The whole town seemed to get livened up instantly: the air became fresher, the roads cleaner, the trees greener, and the people happier.