A、Light speed is millions of times faster than sound speed. B、Light speed is a million times slower than sound speed. C、Light sp

admin2012-11-30  32

问题  
Light travels at a speed that is about a million times faster than the speed of sound. In one second, light travels about 300, 000 km, but sound travels only about 334 meters. 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 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 about four years ago at a speed of nearly 20 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 tars look pretty. They were shining four years ago, but their light has only just reached the earth."

选项 A、Light speed is millions of times faster than sound speed.
B、Light speed is a million times slower than sound speed.
C、Light speed is about millions of times faster than sound speed.
D、Light speed is about a million times faster than sound speed.

答案D

解析 细节辨析题 本题的四个选项表达很接近,要注意区别millions of times,about millions of times和a million times。原文中提到的光速比声速快约一百万倍。
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