The Magic of Sound Music is one of the most beautiful forms of artistic expressions ever invented. In movies and plays, musi

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问题                             The Magic of Sound
    Music is one of the most beautiful forms of artistic expressions ever invented. In movies and plays, music has an added function: it not only moves people but also can shock people. Is it true that an ordinary musical instrument can be so powerful?
    Our eardrums can withstand sound within 20 to 80 decibels. Once sound exceeds this limit, even beautiful music will become ear-splitting noise and harm health. A strong blast of high sound can twist and break a solid iron sheet. 41
    The noise from a plane’s engine is over 140 decibels. However, the sound of a flute is at most a few decibels. 42 It has been proven that people who have worked in an environment with a high sound intensity for a long time suffer varying degrees of heart disease or altered brain waves.
    In movies, sometimes the hero can produce a sound that ordinary people can’t hear and only those who have the same ability can feel. In nature, there is actually sound that is beyond our hearing. In physics, the sound that exceeds 20, 000 Hz is called ultrasonic. 43 It does no harm to health.
    Sound less than 20 Hz is called infrasonic waves. When we move, the air will vibrate. 44 As the frequency of infrasonic waves is close to that of people’s internal organs, infrasonic wave may cause resonance in human bodies. As a result, people’s vision may weaken and internal organs may rupture. However, whether an infrasonic wave can be used as a weapon depends on its intensity. If its intensity is very low, it won’t damage internal organs or a person’s health. 45 When wind blows at a force of 3 or 4 over the sea, it will produce infrasonic waves of several decibels. Only typhoons can produce infrasonic waves of over 100 decibels. At present, scientists can only produce infrasonic weapons in the lab with the help of advanced scientific tools and powerful electric power.
A. High sound of 150 decibels can kill a healthy rat.
B. The vibration of-air can produce infrasonic waves.
C. We cannot play high-pitched music with ordinary musical instruments.
D. If the intensity of infrasonic wave exceeds 160 decibels, it is extremely harmful.
E. Dolphins, whales and bats can make such high-frequency sound
F. Therefore, the sound of ordinary musical instruments cannot harm your health.

选项

答案A

解析 本段要说明,音量超过80分贝,即使是美妙的音乐,对人体也有害。“空41”前面的句子说:一阵高分贝的强烈的冲击波能使一块铁板扭曲和破裂。“空41”的句子应该与高分贝的声音的危害性有关。选项A的“High sound of 150 decibels can kill a healthy rat”是高分贝声音的危害性的又一个例子。从“空41”位置上隐去的句子必是此句。A是答案。
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