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 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 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

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

3.Sunlight obviously (明显地) ______ than the light of the moon

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

Light travels at a speed which is about a million times faster than the speed of sound. In one second, light travels about 300,000km, but sound travels only 344m. You can get some idea of this difference by watching the start of a race. If you stand some distance away from the starter, you can see smoke come from his gun before the sound reaches your ears. This great speed of light produces some strange facts. Sunlight takes about 8 minutes to reach us. If you look at the light of the moon tonight, remember that the light rays（光线）left the moon 1.3 seconds before they reached you. The nearest star is so far away that the light which 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 started on its journey to you before you were born.

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

1. Light speed is ________ than sound speed.

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

3.What does “ it” refer to?

4.The scientific way of saying “ The stars are shining tonight” should be________.

Light travels at a speed which is about a million times faster than the speed of sound. In one second, light travels about 300,000km, but sound travels only 344m. You can get some idea of this difference by watching the start of a race. If you stand some distance away from the starter, you can see smoke come from his gun before the sound reaches your ears. This great speed of light produces some strange facts. Sunlight takes about 8 minutes to reach us. If you look at the light of the moon tonight, remember that the light rays（光线）left the moon 1.3 seconds before they reached you. The nearest star is so far away that the light which 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 started on its journey to you before you were born.

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

Light speed is ________ than sound speed.

A. millions times faster               B. a million times slower

C. about millions of times faster       D. about a million times faster

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 gun before you see the smoke.

B. sound does not travel as fast as light.

C. the sound of the gun will reach you before the man fires his gun.

D. sound travels about a million times faster than light.

What does “ it” refer to?

A. moon light    B. light rays         C. the nearest star        D. the moon

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 be shining four years later.

C. the stars were shining long ago but are seen tonight.

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