The earth is our home.It has air that we can breathe（呼吸）.It has water for us to drink.It has plants and animals that we can eat.It has everything we need to live.
    We are on the earth，but we can see things that are not on the earth.Early in the morning，we can see the sun come up.All day，the sun seems to move across the sky.Later in the day，we can see the sun go down.
    But the sun is not really moving around us.We are the ones who are moving.Every morning，we turn towards the sun.Every night，we turn away from it Every year，we go around it.The earth is our spaceship.All of us in the spaceship are riding around the sun.
    At night，we can often see the moon and stars.From the earth，stars look like little points of light because they are so far away.But stars are really big.A star is a great mas（一团） of burning gas.It gives off light and heat.Our sun is a star.
    There are eight planets moving around our sun.The earth is the third planet around the sun.Some of the planets have moons.A moon goes around a planet just as a planet goes around a star.
    The earth has only one moon.Some planets have more.

（1）Why is the earth our home？ （ no more than 8 words ）

Because it has everything we need to live.

Because it has everything we need to live.

（2）Is the sun really moving around us？ （ no more than 3 words）

No/No，it isn't.

No/No，it isn't.

（3）Why do stars look small？ （ no more than 6 words ）

Because they are so far away.

Because they are so far away.

（4）How many planets move around the sun？ （ no more than 1 word ）

Eight/8.

Eight/8.

（5）How does a moon go？ （ no more than 3 words）

Around a planet.

Around a planet.