1 .

Go     none   call   much   billion   discover   reach   impossible   that   large   has

The earth is a planet and it     1     around the sun. Seven other planets also go around the sun.    2    of them has an environment like     3     of the earth, so scientists do not think they will find life on them. The sun and its planets are     4     the solar system, and our solar system is a small part of a     5    larger group of stars and planets, called the Galaxy or the Milky Way. There are     6    of stars in the Galaxy, and our sun is only one of them.

Scientists have also     7    many other galaxies in the universe. They are very far and their light has to travel for many years to     8     us. So how     9     is the universe? It is     10    to imagine.

2 . If you look at the sky one night and see something moving and shining that you have never seen before, it might be a comet (彗星).
A comet sometimes looks like a star. Like a planet, a comet has no light of its own. It shines from the sunlight it reflects (反射). Like the earth a comet goes around the sun, but on a much longer path than the earth travels.
If a comet isn’t a star, what is it then?
Some scientists think that a large part of a comet is water frozen (冻) into pieces of ice and mixed with iron and rock dust and perhaps a few big pieces of rock. When sunshine melts (融化) the ice in the comet, great clouds of gas go trailing after it. These clouds, together with the dust, form a long tail.
Many people have seen a comet. However, no one knows how many comets there are. There may be millions of comets, but only a few come close enough for us to see.
An Englishman named Edmund Halley, who lived from 1656 to 1742, found out a lot about the paths that comets take through the sky. Some comets move out of our sight and never come back. Others keep coming back at regular times. A big comet that keeps coming back was named after Halley comet, because the last time it came close to the sun and the earth was in the year 1986. Then people all over the world were outside at night to look at it. You will probably be able to see Halley’s comet when it comes near the earth again.
根据短文内容，从题中所给的A、B、C、D四个选项中，选择最佳答案。
1. A comet is like.

A．the sun	B．the moon
C．sunlight	D．the earth

2. A large part of a comet is.

A．water and rock

B．water frozen into pieces of ice and mixed with iron and rock dust and perhaps a few pieces of rock

C．ice, iron and rock dust

D．only a few big pieces of rock

3. Many people.

A．haven’t seen any comets

B．have seen all comets

C．have seen a comet at daytime

D．have seen a comet

4. Some comets keep coming back.

A．at any time

B．at noon

C．at regular times

D．at daybreak (拂晓)

5. When did Halley’s comet come close to the sun and the earth last time?

A．In 1656.	B．In 1742.
C．In 1986.	D．In 1996.

3 . Scientists have always wanted to know more about the other worlds in space.
Years ago, they knew many facts about the moon. They knew how big it was and how far away it was from the earth. But they wanted to know more about it .They thought and thought. At last they found the only way to know more was to send men to the moon.
The moon is about three hundred and eighty-four thousand kilometers away from the earth. A plane can not fly to the moon because the air reaches only 240 kilometers. Then there is no air. But something can fly even when there is no air. That is a rocket.
How does a rocket fly? There is gas in the rocket. When the gas is made very hot inside the rocket, it will rush out of the end of the rocket, so it can make the rocket fly up into the sky.
Rockets can fly far out into space. Rockets with men in them have already reached the moon. Some rockets without men in them have flown to other planets much farther away than the moon. One day rockets may be able to go to any place.
根据短文内容，从题中所给的A、B、C、D四个选项中，选择最佳答案。
1. What does the underlined word “worlds” refer to?

A．moon

B．planets

C．fields

D．sky

2. The moon is about kilometers away from the earth.

A．384000

B．348000

C．3840

D．3480

3. A plane can’t fly to the moon because .

A．it’s too far away

B．it can’t fly without air

C．there is no water on the moon

D．it is too small

4. The hot gas in the rocket is used for .

A．cooking food for the astronauts

B．keeping the man in the rocket warm

C．making the rocket fly up

D．keeping the air in the rocket fresh

5. Rockets without men in them have reached .

A．another star

B．the sun

C．the moon

D．other planets of the sun

4 . Our sun is a star, and nine worlds (天体) move round it. Worlds like these are planets. 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 been anymore. The stars are too far away from us. Stars give out light, but the planets don’t have any light of their own. So we can’t see them. They are 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 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 known Bernard’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 _________.

A．moves round our sun	B．has light of its own
C．can also be called a sun	D．both B and C

2. Which of the following is not true?

A．The earth is one of the sun’s world’s

B．There are millions of suns in the universe

C．The worlds are very bright

D．some stars have planets

3. We can see the planets round our sun. But we can’t see ________.

A．nine worlds in the universe

B．the planets round other stars

C．the satellites round the earth

D．other stars

4. Barnard’s Star moves more quickly than ________.

A．most stars	B．any other star
C．its planet	D．the planets round the sun

5. How can people know that there is a planet 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.

5 . There is nothing more i    1     to life than the sun. W    2     the sun, all living things on the earth would die. The sun is a star. In the sky there are t    3     of stars like the sun. They are as large as the sun and as h    4     as the sun. At night you can see many stars, but in the day you can only see one star—the sun.

The sun is much n    5     to us than any other star. That is w    6     it looks the biggest and brightest of all the stars. The distance (距离) of the sun from the earth is as m    7     as 150,000,000 kilometers. Most stars are thousands of light-years a    8     from the earth.

Do you know what a light-year is? N    9     in the world travels faster than light. It travels 300,000 kilometers per second. And one light-year is the distance that light can travel in one y    10    .

6 . Unless we spend money to spot(认出，发现) and prevent asteroids(小行星) now, one might crash into Earth and destroy life as we know it, say some scientists.
Asteroids are bigger versions of the meteoroids(流星体) that race across the night sky. Most orbit the sun far from Earth and don’t threaten us. But there are also thousands of asteroids whose orbits put them on a collision course with Earth.
But $500 million worth of new telescopes right now, then spend $10 million a year for the next 25 years to locate most of the space rocks. By the time we spot a fatal one, the scientists say, we’ll have a way to change its course.
Is it worth it? Two things experts consider when judging any risk are (i) How likely the event is; (2) How bad the consequences if the event occurs. Experts think an asteroid big enough to destroy lots of life might strike Earth once every 500,000 years. Sounds pretty rare but if one did fall. It would be the end of the world. “If we don’t take care of these bid asteroids, they’ll take care of us,” says one scientist. “it’s that simple.”
The cure, though, might be worse than the disease. Do we really want fleets(舰队，车队) of nuclear weapons sitting around on Earth? “the world has less fear from doomsday(毁灭性) rocks than from a great nuclear fleet set against them.” Said a New York Times article.
1. What does the passage say about asteroids and meteoroids?

A．They are heavenly bodies different in composition.

B．They are heavenly bodies similar in nature.

C．They are more asteroids than meteoroids.

D．Asteroids are more mysterious than meteoroids.

2. What do scientists say about the collision of an asteroid with Earth?

A．It is very unlikely but the danger exists.

B．Such a collision might occur once every 25 years.

C．Collisions of smaller asteroids with Earth occur more often than expected.

D．It’s still too early to say whether such a collision might occur.

3. What do people think of the suggestion of using nuclear weapons to alter the course of asteroids?

A．It sounds practical but it may not solve the problem.

B．It may create more problems than it might solve.

C．It is a waste of money because a collision of asteroids with Earth is very unlikely.

D．Further research should be done before it is proved applicable.

4. We can conclude from the passage that __

A．While pushing asteroids off course nuclear weapons would destroy the world.

B．Asteroids racing across the night sky are likely to hit Earth in the near future.

C．The worry about asteroids can be left to future generations since it is unlikely to happen in our lifetime.

D．Workable solutions still have to be found to prevent a collision of asteroids with Earth.

5. Which of the following best describes the author’s tone in this passage?

A．Optimistic(乐观的)

B．Critical(批评的)

C．Objective(客观的)

D．Arbitrary(武断的)