题目内容

What will they do in the evening？ .
[ A] Go shopping.
[B]Go to a concert.
[C] Go to the cinema.

查看答案

搜索结果不匹配？点我反馈

更多问题

D
To fight a noise by making more noise sounds strange, but that ' s exactly what motor engi-
neers 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 tech-
nique 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) borh 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 bum less fuel and work better. Sorpe 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.
69. Which of the following gives a general idea of how the noise killing system works？
[ A]By producing pressure waves going in the opposite direction.
[ B ] By mixing high frequency sound waves with .low frequency sound waves.
[C]By mixing new sound waves with the noise and sending them out together.
[D]By making copies of the unwanted sound waves and letting them out a little later.

甲公司工程项目的地下隐蔽工程已出现重大安全隐患，2010年5月13日安全生产管理机构下达了停产整改的通知。但是，甲公司在安全隐患尚未排除之前，其项目经理却要求乙某等工人继续施工。对此情形，乙某等工人可以行使的权利是（）。

2010年9月13日在对某施工现场进行检查时，发现尚未完工的大楼内有25名建筑工人居住。施工单位解释由于现场场地狭窄，且工期紧，暂时无法解决这些建筑工人的居住问题。经行政部门核实，施工单位的说法属实。对此问题正确的解决方式是（）。

下列选项中，对保险合同的法律性质表述正确的有（）。