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
2014-05-25
76
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 aboutthe 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,应用了这项设备,还可以降低汽车的重量。所以正确的答案为A。
转载请注明原文地址:https://kaotiyun.com/show/NQud777K
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
ThecelebrationofVeteransDayisheldonNovember11theveryyearintheUnitedStates.Thisdayisset【B1】tohonorandreme
TherearehundredsofTVchannelsintheUnitedStates.AmericansgetalotofentertainmentandinformationfromTV.Mostpeopl
Whatexactlydoesthemanwanttofindout?
Whatexactlydoesthemanwanttofindout?
Wemust______theUnitedStatesfiveyearsinordertoapplyforcitizenship.
Sistersareoftenalikebuttheyaxeneverexactlythesame.Inmany【B1】,onesisterisoftencalled"theprettyone"andthe
YoucanuseyourBusinessTelecardInternationalatanycardphoneintheUnitedKingdom.Hereissomeinformationaboutmaking
Iwasoutoftownatthetime,soIdonotknowexactlyhowit______.
随机试题
背景材料(大意): 受特殊计划生育政策、快速城市化和工业化进程中生育意愿迅速变化等多方面因素影响,我国正在进入快速的老龄化过程。截至2013年底,我国60周岁及以上人口20243万,占总人口的14.9%,65周岁及以上人口13161万,占总人口的9.7%
患者男性,40岁,周期性发热伴全身乏力半年余,否认结核病史。查体:消瘦,双侧颈部锁骨上及双侧腹股沟区触及多发肿大淋巴结,无压痛,心肺检查(一),B超示腹膜后多发肿大淋巴结,TB-Ab(一)。临床拟行67Ga显像,下述67Ga显像方法不正确的是
A.鼠疫和霍乱B.流行性感冒C.艾滋病D.肺炎E.肝癌《中华人民共和国传染病防治法》规定的乙类传染病有
卫生行政部门收到医学会的医疗事故技术鉴定书后,应当对()进行审核。
吕某,女,45岁。因反复“吐血”3天,加重2小时送入急诊。王医生接诊患者后,急查血常规正常,诊断为“上消化道出血”,给予抑酸、保护胃黏膜治疗后留观。留观6小时后患者突然出现咯血,量约300ml,鲜红色,并伴有心慌、胸闷、气喘。刘医生查看患者,查体:T38℃
甲公司为增值税一般纳税人,适用的增值税税率为17%,2015年12月发生如下经济事项:(1)为宣传新产品发生广告费15万元,为拓展产品销售市场发生的业务招待费8万元,均用银行存款支付。(2)确认销售部门12月份发生的职工薪酬10万元,销售部门专
根据税收征管法律制度的规定,下列各项中,不属于税务担保范围的是()。
本题涉及关税、消费税、增值税、城建税、教育费附加。某市大型商贸公司为增值税一般纳税人,兼营商品加工、批发、零售和进出口业务,2020年10月相关经营业务如下:(1)进口高档化妆品一批,支付国外的买价220万元、购货佣金6万元、国外的经纪费4万元;支付运
广西壮族自治区()花山岩画景观已被列为世界遗产名录。
(12)用于把摄影作品、绘画作品输入到计算机中,进而对这些图像信息进行加工处理、管理、使用、存储和输出。
最新回复
(
0
)