新概念英语青少版3A_Unit_11_Turn_it_down.ppt

Unit 11 Turn it down! Do you like these? 你对分贝了解多少？ 分贝（decibel）dB 分贝是以美国发明家亚历山大·格雷厄姆·贝尔（英国人，后移居美国）命名的，他因发明电话（1875年贝尔制成了实用的电话装置，1876年建起了世界上第一家电话公司。）而闻名于世。 你知道一个声音与另一个声音结合时，会产生什么结果吗？我们都知道60个苹果加60 个苹果，等于120个苹果。但是，这并不适用于以分贝来表示的声音。事实上，60分贝加60分贝只等于63分贝。 分贝对人的影响有什么？ ★ 10~20分贝几乎感觉不到。 　　 ★ 20~40分贝相当于轻声说话。 　　 ★ 40~60分贝相当于室内谈话。 　　 ★ 60~70分贝有损神经。 你对分贝了解多少？ 　★ 70~90分贝很吵。长期在这种环境下学习和生活，会使人的神经细胞逐渐受到破坏。 　　 ★ 90~100分贝会使听力受损。 　　 ★ 100~120分贝使人难以忍受，几分钟就可暂时致聋。 　　 一般声音在30分贝左右时，不会影响正常的生活和休息。 而达到50分贝以上时，人们有较大的感觉，很难入睡。 维塔斯的高音是105分贝，而飞机起飞时螺旋桨发出的声音才110分贝！ Unit 11 Turn it down! Lucy: Dad, that music’s loud! Turn it down! William: Sorry, Lucy! Am I interrupting your homework? Lucy: It’s not that, Dad. We had a lesson today about hearing. Look at this. Notes on the Text interrupt interruption n. e.g: He tried to speak, but she interrupted him. interrupt 是打断的意思，主要打断别人正在进行的事情，如谈话，或者工作。 disturb是打扰的意思，主要是打扰别人休息。 bother是烦扰的意思，主要是指在某一时间段里，持续打扰别人并使别人烦恼。 that, 代词，指代前面的一整句。 Unit 11 Turn it down! One person in seven in the UK is deaf, and many of them are deaf because of noise. For most people, the safe limit is 85 decibels(dB) for continuous noise, and 103 dB for sudden noise. After fifteen minutes at 105 dB, most people will have some damage to their hearing. Notes on the Text One person in seven in the UK is deaf 谓语动词用单数，两个in分别表示时间和地点，不做主语。 because of，of为介词，后跟名词。 e.g: Im here because of you. because conj. 其后接原因状语从句或回答以why开头的问句； e.g: Because he is ill, he is absent today. decibel 复数：decibels e.g: Continuous exposure to sound above 80 decibels could be harmful. Unit 11 Turn it down! Music in nightclubs is often much louder than the safe limit.19% of young people listen to their MP3 players at 105 to 110 dB for many hours. 75% of them will experience ‘ringing in the ears’,and they will feel a bit deaf. If they are lucky, this will last for one or two days. If they are unlucky, the damage will last f