Lighttravelsataspeedwhichisaboutamilliontimesfastert...

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問題詳情：

light travels at a speed which is about a million times faster than the speed of sound. In one second, light travels about 300,000 km, 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 (產生) 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（光線）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（情況）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 shinning tonight.” We have to say, “The stars look pretty. They were shining four years ago but their light has only just reached Earth.”

61. 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.

62. Sunlight clearly _____ 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

63. What does “ it ” in the second paragraph refer to?

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

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

A stars have been shining all the time.