Our sun is a star, and nine worlds move round it. Worlds like these are planets (行星).

But there are other stars, other suns. Not only thousands of them, but millions of them. Do different stars have planets? We can see the planets round our own sun. But we haven’t seen any more. The stars are too far away from us. Stars give out (发出)light, but the planets don’t have any light of their own. So we can’t see them. They’re too far, and too dark.

Still, we can tell that some stars have planets. While a big planet goes round, it pulls its star to one side. And sometimes we can see this, Then we know that the star has a planet.

For example, Barnard’s Star（巴纳德星）is a small red star. And it is the quickest star in the universe. But sometimes it moves slower, and then quicker again. We have know Barnard’s Star for many years, and now we are sure it has a planet.

A star is a large body in the universe.it________.

        A.moves round our sun            B.has light of its own      

        C.can also be called a world        D.both B and C

Which of the following is not true?

        A.The earth is one of sun’s worlds     B.There are millions of suns in the universe.       

 C. The worlds are very bright.        D.Some stars have planets

Barnard’s Star moves more quickly than _______.

        A.most stars          B.any other star       

 C.its planet           D.the planets round the sun

How can people know that there is a plante round Barnard’s Star?

        A.Sometimes they see that the planet pulls the star to one side and makes it move slower

.    B.The planet is shining.         

        C.The planet is next to our earth.        

D.The planet is a red one.

Our sun is a star, and nine worlds move round it. Worlds like these are planets (行星).
But there are other stars, other suns. Not only thousands of them, but millions of them. Do different stars have planets? We can see the planets round our own sun. But we haven’t seen any more. The stars are too far away from us. Stars give out (发出)light, but the planets don’t have any light of their own. So we can’t see them. They’re too far, and too dark.
Still, we can tell that some stars have planets. While a big planet goes round, it pulls its star to one side. And sometimes we can see this, Then we know that the star has a planet.
For example, Barnard’s Star（巴纳德星）is a small red star. And it is the quickest star in the universe. But sometimes it moves slower, and then quicker again. We have know Barnard’s Star for many years, and now we are sure it has a planet.
【小题1】A star is a large body in the universe.it________.

Our sun is a star, and nine worlds move round it. Worlds like these are planets (行星).

But there are other stars, other suns. Not only thousands of them, but millions of them. Do different stars have planets? We can see the planets round our own sun. But we haven’t seen any more. The stars are too far away from us. Stars give out (发出)light, but the planets don’t have any light of their own. So we can’t see them. They’re too far, and too dark.

Still, we can tell that some stars have planets. While a big planet goes round, it pulls its star to one side. And sometimes we can see this, Then we know that the star has a planet.

For example, Barnard’s Star（巴纳德星）is a small red star. And it is the quickest star in the universe. But sometimes it moves slower, and then quicker again. We have know Barnard’s Star for many years, and now we are sure it has a planet.

1.A star is a large body in the universe.it________.

2.Which of the following is not true?

3.Barnard’s Star moves more quickly than _______.

4.How can people know that there is a plante round Barnard’s Star?

阅读理解

　　The earth is not the only body that travels round the sun. With it are eight other planets, fellow members of the sun's family. Two of them are nearer while the other six are farther from the sun than the earth is. The farther they are, the longer trips they make round the sun. People noticed long ago that these traveling bodies moved round in the sky in certain paths.

　　We know that every little bit of matter in the universe pulls upon every other bit of matter. The pull between two bodies is proportional(成比例) to the product(乘积) of their masses. Because the sun is so large, the pulls between the sun and the planets are thus great. If it were not for these pulls, the planets would fly off into space. In the same way there is a pull between the earth and the moon, which keeps the moon traveling in its orbit (轨道) around our planet, the earth. The pull holds you to its surface, and pulls back the ball which you throw into the air. Of course the ball also pulls on the larger earth, but the earth is so much larger that the pull is not noticed.

1．The earth travels a larger circle around the sun than ________.

[　　]

A．six of the other planets

B．two planets in the same family

C．most planets in the universe

D．the moon

2．The planets move around the sun because of ________.

[　　]

A．the gravity of the sun only

B．the pull of the planets on one another

C．the pull between the planets and the sun

D．the proportional gravity

3．If objects didn't have gravity ________.

[　　]

A．the earth would not travel in the space

B．the moon would move away from the earth

C．the sun would not exist

D．the planets of the sun family form another family