Question

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(距離) 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(太陽光) 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(顯然的) ______ 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

 

Answer 1

【答案】

 

1.D

2.B

3.A

4.C

【解析】

試題分析：這篇短文中作者主要介紹了光的傳播速度要遠(yuǎn)遠(yuǎn)高于聲的傳播。文章又向我們描述了一種奇怪的自然現(xiàn)象，引起了人們的思考。

1.細(xì)節(jié)理解題。根據(jù)短文第一句話Light travels at a speed which is about a million times faster than the speed of sound.可知光的傳播速度比聲音的傳播速度要快一百萬倍；故選D。

2.細(xì)節(jié)理解題。根據(jù)短文第一段最后一句話If you stand some distance(距離) away from the starter, you can see smoke from his gun before the sound reaches your ears.可知，看到煙霧要比聽到聲音早，即聲音和光傳播的并不是一樣快的，其他三項(xiàng)表述錯(cuò)誤；故選B。

3.推理判斷題。根據(jù)短文第二段Sunlight(太陽光) 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.兩句可知，太陽光傳播的距離要遠(yuǎn)遠(yuǎn)大于月光；故選A。

4.推理判斷題。根據(jù)短文最后一句話“The stars look pretty. They were shining four years ago, but their light has only just reached the earth.”可知我們今晚看到的星光是四年前就已經(jīng)發(fā)射出來了，只是我們現(xiàn)在才看到；與C項(xiàng)描述相吻合；故選C。

考點(diǎn)：科普類短文閱讀。