Researchers at Brigham found about one in five teenagers now have some degree of hearing damage. The researchers did not say why hearing loss has risen, but other experts have strong suspicions. One likely culprit, they say, is MP3 players.

    An MP3 player can be dangerous to hearing when its decibel level is turned up too high. High-decibel sounds can damage nerve endings, called hair cells. If a sound is loud enough, the damage can be permanent. A loud sound can shake the membrane (薄膜) on which the hair cells sit- “like an earthquake”. That shake can break or even uproot hair cells. When that happens, the hair cells are finished. Human ears cannot regrow hair cells. Therefore, when listening to an MP3 player, set a volume limit and avoid exposure to loud sounds.

    On the other hand, the loudness of today's music may not be totally under your control. Music companies have been purposely turning up the volume. It's a trend called the fight for loudness.

    Play a CD from the 1990s. Then play a newly released tune. Don't touch the volume control. You'll probably notice that the new CD sounds louder than the old one. Why? Sound engineers who create CDs are using dynamic range compression (压缩), a technology that makes the quiet parts of a song louder and the loud parts quieter. The overall effect of compression is a louder recording.

    Many musicians and sound engineers aren't pleased. They say that compression is driving down the quality of today, s music, making it sound flat and blaring. Gray Hobish, a sound engineer, explains that music should be a combination of loudness and softness. But music companies want to make music louder so it will stand out. That's important in the competition among recording companies.

    What about listeners? Many teenagers listen to music on the go in noisy places and through headphones, all of which reduce sound quality. So young listeners may not notice the poorer quality of modem recordings. “To their ears,” says Hobish, “the music sounds fine. And they are not aware of the hidden threat of the music they are enjoying.”

阅读下文，完成小题。

天下第一好事，还是读书

季羡林

      ①古今中外赞美读书的名人和文章，多得不可胜数。张元济先生有一句简单朴素的活：“天下第一好事，还是读书。”“天下”而又“第一”，可见读书的重要性。

      ②为什么读书是一件“好事”呢？

      ③也许有人认为，这问题提得幼稚而又突兀。这就等于问“为什么人要吃饭”一样，因为没有人反对吃饭，也没有人说读书不是一件好事。

      ④但是，我却认为，凡事都必须问一个“为什么”，事出都有因，不应当马马虎虎，等闲视之。现在就谈一谈我个人的认识，谈一谈读书为什么是一件好事。

      ⑤凡是事情古老的，我们常常说“自从盘古开天地”。我现在还要从盘古开天地以前谈起，从人类脱离了兽界进入人界开始谈。人成了人以后，就开始积累人的智慧，这种智慧如滚雪球，越滚越大，也就是越积越多。禽兽似乎没有发现有这种本领，一只蠢猪一万年以前是这样蠢，到了今天仍然是这样蠢，没有增加什么智慧。人则不然，不但能随时增加智慧，而且根据我的观察，增加的速度越来越快，有如物体从高空下坠一般。到了今天，达到了知识爆炸的水平。

      ⑥人类千百年以来保存智慧的手段不出两种：一是实物，比如长城等；二是书籍，以后者为主。在发明文字以前，保存智慧靠记忆；文字发明了以后，则使用书籍。把脑海里记忆的东西搬出来，搬到纸上，就形成了书籍，书籍是贮存人类代代相传的智慧的宝库。后一代的人必须读书，才能继承和发扬前人的智慧。人类之所以能够进步，永远不停地向前迈进，靠的就是能读书又能写书的本领。我常常想，人类向前发展，有如接力赛跑，第一代人跑第一棒，第二代人接过棒来，跑第二棒，以至第三棒、第四棒，永远跑下去，永无穷尽，这样智慧的传承也永无穷尽。这样的传承靠的主要就是书，书是事关人类智慧传承的大事，这样一来，读书不是“天下第一好事”又是什么呢？

      ⑦但是，话又说了回来，中国历代都有“读书无用论”的说法，读书的知识分子，古代通称之为“秀才”，常常成为取笑的对象，比如说什么“秀才造反，三年不成”。这话不无道理。在古代---请注意，我说的是“在古代”，今天已经完全不同了---造反而成功者几乎都是不识字的地痞流氓，中国历史上两个“马上皇帝”，开国“英主”，刘邦和朱元璋，都属此类。诗人只有慨叹“可惜刘项不读书”。“秀才”最多也只有成为这一批地痞流氓的“帮忙”或者“帮闲”，帮不上的，就只好慨叹“儒冠多误身”了。

      ⑧但是，话还要再说回来，中国悠久的优秀的传统文化的传承者，是这一批地痞流氓，还是“秀才”？答案皎如天日。这一批“读书无用论”的现身“说法”者的“高祖”“太祖”之类，除了镇压人民剥削人民之外，只给后代留下了什么“陵”之类，供今天搞旅游的人赚钱而已。他们对我们国家竞无贡献可言。

      ⑨总而言之，“天下第一好事，还是读书”。