阅读短文,写出句中所缺的单词
The sky usually looks light b________. If you go to the top of the highest mountain, there is less a________ between you and the sun to scatter (分散) the sunlight, the sky would be dark blue. If you take a space s________ high above the earth, there is no air at a________ to scatter the sunlight, the sky would be so dark that it would be black.
Sometimes the sky doesn't l________ blue. A sunrise (日出) and sunset (日落), the light from the s________ is scattered in such a way that you see red, orange, and other colors in the s________.