A lot of animals are afraid during an eclipse of the sun. Birds stop singing. Sometimes people too are afraid. Astronomers know the dates of eclipses and they are not afraid. The old astronomers of Babylon and Egypt had no telescopes; but the sky in those countries is usually clear，and so they could watch the stars easily. They studied everything in the sky and they also noticed both total and partial eclipses.
基于1个网页-相关网页
应用推荐