首页
登录
职称英语
[originaltext] The idea of fighting a noise by making more noise sounds stra
[originaltext] The idea of fighting a noise by making more noise sounds stra
游客
2023-09-02
68
管理
问题
The idea of fighting a noise by making more noise sounds strange, but that’s exactly what motor engineers are doing in Germany and some other countries.
Carmakers’ research and development laboratories have already proved that mixing in more noise with the help of loudspeakers can reduce the unwanted noise.
Physicists have known about the technique for a long time. Sound is made up of pressure waves in the air. If two sound waves of the same frequency mix so that the highest point of one wave happens at the same time with the lowest point of the other wave, the result is no sound. Therefore, by producing a perfect copy of the noise and delaying it by half a wave cycle, we can kill the unwanted noise. Using this technique many carmakers are racing to develop noise-killing systems both inside and outside the cars.
Another good thing about the use of noise-killing systems is that it saves the need for a silencer, which not only reduces the weight of a car, but also makes the motor burn less oil and work better.
Some engineers believe that the noise-killing system will be used in most cars by 1996. But the carmakers haven’t decided if they will put it into production because it would add several hundred dollars to the cost of their cars.
Questions 29 to 31 are based on the passage you have just heard.
29. Which gives a general idea of how the noise-killing system works?
30. What can the noise-killing system do besides its main function?
31. Why isn’t the noise-killing system yet popular?
选项
A、It can make a car lighter.
B、It can make a car faster.
C、It can reduce the cost of a silencer.
D、It can improve the performance of a silencer.
答案
A
解析
选项中的It can make/reduce/improve等表明,本题可能考查It的作用。短文中提到噪音消除系统的优点之一:reduces the weight of a car。A)中的make a car lighter是对此的同义转述,故答案为A)。
转载请注明原文地址:http://tihaiku.com/zcyy/2980189.html
相关试题推荐
[originaltext]Tosucceedinajobinterview,youshoulddemonstratecertain
[originaltext]Tosucceedinajobinterview,youshoulddemonstratecertain
[originaltext](33)Ourenvironmentisbeingpollutedfasterthannaturean
[originaltext]Iwillletyouknowthatthere’sabigdifferencebetweenund
[originaltext]Iwillletyouknowthatthere’sabigdifferencebetweenund
[originaltext]W:I’mnotswimminginthelakeunlessitwarmsupoutsidetoday.
[originaltext]W:I’mnotswimminginthelakeunlessitwarmsupoutsidetoday.
[originaltext]W:I’mnotswimminginthelakeunlessitwarmsupoutsidetoday.
[originaltext]W:I’mnotswimminginthelakeunlessitwarmsupoutsidetoday.
[originaltext]Everyartistknowsinhisheartthatheissayingsomething
随机试题
Onceuponatime,youbelievedinthetoothfairy.Youcountedonthestabil
不锈钢管的连接方式多样,常见的管件类型有()。A.压缩式 B.压紧式 C.
风险的成本估算完成后,可以针对风险表中的每个风险计算其风险曝光度。某软件小组计划
对于瘙痒症以下叙述不恰当的是A.某些物理、化学刺激及药物也可引起本病的发生 B
男,37岁。因长期工作紧张,而且不能一日三餐按时吃饭,造成胃溃疡,他应服的最好药
下列关于利用未公开信息罪说法正确的是( )。A.主观方面不知道是未公开信息而加
抑制胃酸分泌的代表药物是A.丙谷胺 B.西咪替丁 C.哌仑西平 D.枸橼酸
网络公司钱经理说:“我们要把传承中国优秀传统文化当作本职工作,在游戏开发中坚持(
A.3 B.7 C.10 D.70
在Excel中,下列说法不正确的的是()。A、可以对建立的图表进行缩放和修改
最新回复
(
0
)