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  3. 共用题干 第二篇The Magic of SoundMusic is one of the most beautiful forms of artist...

共用题干 第二篇The Magic of SoundMusic is one of the most beautiful forms of artist...

admin2020-12-24  19
问题 共用题干
第二篇
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.
Our eardrums can withstand sound within 20 to 80 decibels（分贝）.Once sound exceeds this limit , even beautiful music will become ear-splitting noise and harm health.A strong blast（响声）of high sound can twist and break a solid iron sheet.High sound of 150 decibels can kill a healthy rat.
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 20,000Hz is called ultrasonic（超音波的）.Dolphins, whales and bats can make such high-frequency sound.It does no harm to health.
Sound less than 20Hz is called infrasonic（次声）waves.When we move, the air will vibrate.The vibration of air can produce infrasonic waves.As the frequency of infrasonic waves is close to that of people's internal organs, infrasonic wave may cause resonance（共振）in human bodies.As a result,people's vision may weaken and internal organs may rupture（断裂）.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.If the intensity of infrasonic wave exceeds 160 decibels,it is extremely harmful.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.
选项 An ultrasonic sound______.
A:is very loud
B:does harm to people's health
C:cannot be heard by people
D:is produced by the hero in movies
答案C
解析本篇文章主要讲了声音的奇妙之处以及超声波和次声波的一些特征。
根据文章的标题“The Magic of Sound"以及全文可知，文章最恰当的标题为C项。其余选项表述都不全面。
根据第二段第一、二句可知，我们的耳膜可以承受的声音在20分贝到80分贝之间，只要超过了这个界限，再美妙的音乐也会成为噪音，损害健康。由此可知，音乐也可能会对人的健康造成危害。
根据第二段第一、二句可知，我们的耳膜可以承受的声音在20分贝到80分贝之间，超过了这个界限，再美妙的音乐也会成为噪音，损害健康。由此可见，超过80分贝的声音对人是有害的。
第三段第二句表明，自然界中存在人类听不到的声音。根据第三段第三句可知，这种超过两万赫兹的声音在物理学中被称为超声波。由此可知，超声波是人类听不到的声音。
根据第四段第四句可知，当次声波的频率与人体内部器官的频率相当时，就会对人体造成危害，又由常理可知振动会产生声音，可推断出人体内存在次声波，因此选择B项。只有当次声波频率与人体内部器官的频率相近时，次声波才会对人有害，所以A项错误；只有超过 160分贝的次声波才能被用作致命武器，并且由最后一段最后一句“At present, scientists can only produce infrasonic weapons in the lab…”可知，次声波用作致命武器还只是实验室的实验结果，现实中并没有出现，所以C项错误；最后一段没有表明次声波可以改善视力，所以D项错误。
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