首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
To fight a noise by making more noise sounds strange, but that’ s exactly what motor engineers are doing in Germany and some oth
To fight a noise by making more noise sounds strange, but that’ s exactly what motor engineers are doing in Germany and some oth
admin
2012-10-16
88
问题
To fight a noise by making more noise sounds strange, but that’ s exactly what motor engineers are doing in Germany and some other countries.
Carmaker’ s research and development laboratories have already proved that mixing 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(频率) mix so that the highest point of one wave happens at the same time as 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 (周期) ,we can kill the unwanted noise. Using this technique many carmakers are racing to develop noise killing systems (系统)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; this not only reduces the weight of a car, but also makes the motor burn less fuel and work better.
Some engineers believe that the noise killing system will be used in most cars within a few years. But the carmakers haven’t decided if they will carry it into production because it would add several hundred dollars to the cost of their cars.
Besides its main use the noise killing system can______.
选项
A、make a car lighter
B、make a car quieter
C、reduce the cost of a silencer
D、improve the performance of a silencer
答案
A
解析
判断推理题。通过文章第三段:Another good thing about the use of noise killing systems is that it saves the need for a silencer;this not only reduces the weight of a car…可知,应用了这种设备,还可以减少汽车的重量。所以正确的答案为A。
转载请注明原文地址:https://kaotiyun.com/show/0Swd777K
本试题收录于:
公共英语二级笔试题库公共英语(PETS)分类
0
公共英语二级笔试
公共英语(PETS)
相关试题推荐
Ican’talwaysfigure______whatmyteachermeansinclass.
Whatistheprobablerelationshipbetweenthespeakers?
Wheredoesthisconversationtakeplace?
Whatisthecompanygoingtodo?
Wheredoesthisconversationmostprobablytakeplace?
Ifthewomanhastoaskforasickleave,whoshouldsheturnto?
YoucanuseyourBusinessTelecardInternationalatanycardphoneintheUnitedKingdom.Hereissomeinformationaboutmaking
Whatmustyoudofirstwhenmakingavalentinebox?
Marywas______byherneighbour’sruderemarks.
Danbyleftwordswithmysecretary______hewouldcallagainintheafternoon.
随机试题
A.菌陈蒿汤B.菌陈术附汤C.菌陈五苓散D.犀角散E.逍遥散治疗阳黄热重于湿的主方为
男,28岁。自感低热、乏力、食欲不振,有盗汗、体重下降、呼吸困难、胸痛等表现,就医诊断为浸润型肺结核,收入院抗结核治疗。关于疾病防治及护理措施不妥的是
母牛倒地不起综合征主要表现经两次以上补钙补糖仍不能站立,不可能的原因是()。
男,5岁。发热1天,腹泻6~7次,为黏液性脓血便,腹痛伴里急后重,病前吃过未洗的黄瓜。粪便常规检查:黏液便,红白细胞满视野。诊断为细菌性痢疾,其类型属于
下列有关皮内注射的操作,描述错误的是
急产是指总产程不超过()
“只要再多走一小步,仿佛是向同一方向迈出的一小步,真理便会变成错误。”这句话意味着()。
历史的人要办历史的事,既不要超越历史,去干那些办不到的事情;也不要推卸历史的责任,该干的事情也不去办。对这句话理解正确的是()。
中世纪西欧的国际贸易具有转运贸易的性质,与之相联系许多国际贸易城市发展繁荣,其中最为典型的是()。
请举例说明新贸易保护主义对我国企业的影响。
最新回复
(
0
)