阅读理解。

     We know the sun, the earth and the moon are in the universe. We see the sun in the daytime

and the moon in the night.

      The sun is much bigger than the earth, and the earth is bigger than the moon. So the sun is

the biggest and the moon is the smallest. The earth goes round the sun day and night. It does at

30 kilometers a second.

     The moon is our satellite (卫星) . It is also our neighbor. It goes round the earth all the time.

The moon goes at 8 kilometers a second. The moon can't give out light or heat itself, and nothing

can live on it.

     Men live on the earth, which is going round itself all the time.  Then the earth gives us lives, food,

water and so on. We must get on well with it.

根据短文内容和首字母，补全下面的单词。

1. The sun is the b_____ of the three.

2. The e_____ is bigger than the moon, but s____than the sun.

3. The m_____  goes round the earth.

4. We can see the moon in the n _____.

5. Men must get on w_____  with the earth.