Light travels at a speed which is about a million times faster than the speed of sound. You can get some idea of this difference by watching the start of a race. If you stand some distance(距离) away from the starter, you can see smoke from his gun before the sound reaches your ears.

This great speed of light produces some strange facts. Sunlight(太阳光) takes about 8 minutes to reach us. If you look at the light of the moon tonight, remember that the light rays left the moon 1.3 seconds before they reached you. The nearest star is so far away that the light that you can see from it tonight started to travel towards you four years ago at a speed of nearly 2 million km. per minute. In some cases, the light from one of tonight’s stars had started on its journey to you before you were born.

Thus, if we want to be honest, we can’t say, “The stars are shining tonight.” We have to say instead, “The stars look pretty. They were shining four years ago, but their light has only just reached the earth.”

1.Light speed is ______ sound speed.

A. as fast as                          

B. a million times slower than

C. about millions of times faster than     

D. about a million times faster than

2. If you stand 200 meters away from a man who is firing a gun to start a race, you will find out that ______.

A. you can hear the sound before you see the smoke

B. the sound does not travel as fast as light

C. the sound will reach you before the man fires

D. sound travels about a million times faster than light

3.Sunlight obviously(显然的) ______ than the light of the moon.

A. has to travel a greater distance          

B. moves less quickly

C. travels much more quickly            

D. is less powerful

4. The scientific way of saying "The stars are shining tonight" should be ______.

A. the stars have been shining all the time

B. the stars seen tonight will shine four years later

C. the stars were shining long ago but seen tonight

D. the starlight seen today could be seen four years ago

 

 

1. What was the s   ▲    of the car at the time of the accident?

2.He was sitting a   ▲    a group of children, telling them a story.

3.The room is very dark. I can't see anything c   ▲    without a light.

4.Kindness is the language that even the b   ▲   can see and the deaf can hear.

5.Even children can understand the story because it's written in very s   ▲   English.

6. This dictionary    ▲   （包括）almost all the English verbs.

7.Cleaning the car is one of my least favorite    ▲   （工作）.

8.Ann is    ▲   （安排)a surprise party for Russell's birthday.

9.The best    ▲   （治疗）for a cold is to rest and drink lots of water.

10.I    ▲   （借给）my penknife to someone, but I can't remember who it was now.

 

When you look at the sky at night, the moon looks bigger than the stars. Actually, the moon is much smaller than the stars and the sun. It's much smaller than the earth. But the moon is much closer to us than any star. That is why it looks so big. If you hold a coin close to your eye, it looks big. If you look at it across the moon, it looks small.
The moon moves around the earth. It makes one trip in about four weeks. The moon looks flat to us. But it is a round ball, like the earth.
People once thought the moon had fire on it. They thought the fire made it bright. Now we know the moon is like a mirror. It gets its light from the sun.
Our sunlight comes from the sun, too. What is the sun? The sun is a star. The stars we can see have their own light. There are many big stars we cannot see. Their light had burned out. Others are still bright, but they are so far away that we cannot see them. The sun looks bigger and much brighter than other stars because it is the nearest of all stars. The sun and the other stars we see are very hot, but the air around us saves us from the heat of the sun.
The sun gives us light and warmth. It makes plants grow and turns leaves green. It makes life possible on our earth. It is a life giving star.
【小题1】 It takes _______ for the moon to go around the earth.

A．more than a week

B．nearly a month

C．half a year

D．more than a year

【小题2】 The moon is bright because _______.

A．there is some fire on it	B．it is near the sun, too
C．there is a big mirror on it	D．it can get light from the sun

【小题3】 The passage tells us _______.

A．the sun is not the biggest star	B．the sun is bigger than any other star
C．only the sun can shine	D．the sun is one of the farthest stars to us

【小题4】 Why do we call the sun "a life giving star"?

A．Because it gives us warmth.

B．Because there are some living things on it.

C．Because plants and animals can't live without it.

D．Because people have to live in the dark without it.

根据学过的课文，判断正（T）误（F）

The Earth is a planet and it goes around the Sun．Seven other planets also go around the Sun．None of them has an environment with air，so people and things cannot grow．The Sun and its planets are called the solar system．The solar system is a small part of our galaxy．

The stars we see at night are the suns in other solar systems．There are more than 200 billion stars in our galaxy，called the Milky Way，and our Sun is only one of them．

But scientists have discovered many other galaxies in the universe．They are a long way away and their light has travelled for many years to reach us．It is hard to understand how large the universe is．

Scientists have sent lots of spacecraft to look at other planets in our solar system，and some spacecraft have gong beyond the solar system．However，no one has discovered any life in space yet．

But why has no one from other planets sent us a message？Have they tried to send information to us？With so many stars in the universe，are we alone，or is there life out there in space？We don’t know．．．yet．

1.The Sun is one of the Earth planets．

2.There is more than one galaxy in our solar system．

3.．There are more than 200 billion stars in the Milky Way．

4.．Scientists have found life on other planets．

5.They’ve received no messages from space．