第12课（225字2分钟）

Passage Twelve

（K9 level）

1. The idea of fighting noise with more noise may seem odd, but this is exactly what car engineers in Germany and other countries are doing.

2. Research and development labs at car manufacturers have already shown that adding more noise through loudspeakers can help reduce unwanted sounds.

3. Physicists have understood this method for a long time.

4. Sound consists of pressure waves traveling through the air.

5. If two sound waves of the same frequency meet in such a way that the peak of one wave lines up with the trough of the other, the result is complete silence.

6. By creating a perfect copy of the unwanted noise and delaying it by half a cycle, we can cancel out the noise completely.

7. Many car manufacturers are quickly working to create noise-canceling systems for both inside and outside the vehicles.

8. One of the benefits of these noise-canceling systems is that they remove the need for a silencer, which not only reduces a car's weight but also helps the engine burn less fuel and perform better.

9. Some engineers predict that most cars will use noise-canceling systems by 2005.

10. However, car manufacturers haven't yet decided whether to put the technology into production, as it would add several hundred dollars to the price of the cars.

生词表（New Words）

1. idea 想法 fighting 对抗 noise 噪音

odd 奇怪 engineers 工程师  

2. research 研究 development 开发 manufacturers 制造商

loudspeakers 扬声器  

3. physicists 物理学家 method 方法  

4. sound 声音 pressure 压力 waves 波

traveling 传播 air 空气  

5.frequency 频率 peak 峰值 trough 谷值

result 结果 silence 静音  

6.creating 创建 copy 复制 delaying 延迟

cycle 周期 cancel 消除 completely 完全  

7.manufacturers 制造商 systems 系统 vehicles 汽车  

8. benefits 好处 silencer 消音器 weight 重量

fuel 燃料 engine 发动机 perform 提高  

9. engineers 工程师 predict 预测  

10. manufacturers 制造商 decided 决定 technology 技术

production 生产 cost 价格 dollars 美元

1. 用更多的噪音来对抗噪音的想法可能看起来很奇怪，但这正是德国和其他国家的汽车工程师正在做的事情。

2. 汽车制造商的研究和开发实验室已经证明，通过扬声器加入更多的噪音可以帮助减少不需要的声音。

3. 物理学家很早以前就已经了解了这种方法。

4. 声音是由在空气中传播的压力波组成的。

5. 如果两个相同频率的声波相遇，并且一个波的峰值与另一个波的谷值对齐，结果就是完全的静音。

6. 通过创建不需要的噪音的完美复制品并将其延迟半个周期，我们可以完全消除噪音。

7. 许多汽车制造商正在快速研发用于车内和车外的噪音消除系统。

8. 这些噪音消除系统的一个好处是，它们不再需要使用消音器，这不仅能减轻汽车的重量，还能帮助发动机减少燃料消耗并提高性能。

9. 一些工程师预测，大多数汽车将在2005年使用噪音消除系统。

10. 然而，汽车制造商尚未决定是否将这一技术投入生产，因为这会让汽车的价格增加几百美元。