Our nearest neighbor is the moon. In the sky,  the moon and the sun seem to be of the same size because the moon is much nearer.
The moon makes the tides—the changes in the level of the sea. The moon and the sun together pull the sea. In some parts of the world,  the difference between "high tide" (when the sea is very near to the land) and " low tide" (when the sea is far away from the land) is very big. This is very important for ships.
    The moon is very different from the Earth. Gravity on the moon is six times weaker than that on the Earth. There isn't any air. During the day, it is very, very hot but at night it is very, very cold. Nothing can live on the moon.
    If the moon goes between the Earth and the sun,  we have an eclipse of the sun(日食) . The moon stops the light from the sun and we have night in the day.
    If the Earth goes between the moon and the sun, we have an eclipse of the moon. The moon goes into the shadow(影子) of the Earth and it disappears for a few minutes.

选词填空

已    以

①我____后见不到灰雀了。

②灰雀____经飞走了。

在     再

③我____也见不到灰雀了。

④一只灰雀停____树上。

秋天到了，满山的红叶、金灿灿的____、红彤彤的____，这些都是秋天美丽的标志。