Passage Four
Unwanted sound, or noise, such as that produced by airplanes, traffic, or industrial machinery, is considered a form of pollution. Noise pollution is at its worst in densely populated areas. It can cause hearing loss, stress, high blood pressure, sleep loss, distraction (注意力分散), and lost productivity!
Sounds are produced, by objects that vibrate (振动), at a rate that the ear can detect. This rate is called frequency and is measured in hertz (赫兹), or vibrations per second. Most humans can hear sounds between 20 and 20,000 hertz, while dogs can hear high pitched sounds (高频声音) up to 50,000 hertz. While high frequency sounds tend to be more hazardous (危险的) and more annoying to heating than low frequency sounds, most noise pollution damage is related to the intensity of the sound. Measured in decibels (分贝), noise intensity can range from zero, the quietest sound the human ear can detect, to over 60 decibels. Conversation takes place at around 40 deci
A. Sounds of 15,000 hertz.
B. Sounds of 20,200 hertz.
C. Sounds of 30,000 hertz.
D. Sounds of 50,000 hertz.
| Examinations have a longer history in
China than in any other country, yet it is today an issue around in which
controversy flourishes. At each stage of their school lives children are faced
with exams: exams to enter junior middle school, senior middle school,
vocational school, colleges and universities. As a result of having constantly
to think of these hurdles facing them children find themselves under constant
pressure, unable to take time off from studying exam-oriented subjects to relax
with friends or to develop other interests. Within school the concentration on
exam success leads to the neglect of courses which are not central to the
examinations and a method of teaching and learning which emphasizes training the
ability to do well in tests but neglects developing the ability to think
creatively. Despite su A. Examinations are the only objective way of selecting students. B. Examinations are the only objective way to eliminate the problem of corruption. C. Examinations can tell us that too much anxiety can be a bad thing. D. Examinations can better stimulate students to study. [填空题]冬季登高或上车顶作业时，应先（），确认脚蹬子，手把杆完好。
[多选题]《20kV及以下配电网工程预算定额 第四册 电缆工程》（2016年版）中规定，电缆试验包括：（）。
A.A、电缆绝缘遥测 B.B、直流耐压试验 C.C、交流耐压试验 D.D、电阻比试验 E.E、电缆局放试验 [单选题]对于车载设备的管理中,车载摄像头的角度( )。
A.左右调整 B.看情况调整 C.禁止调整 D.上下调整 [单选题]当受到冲击和碰撞时，首先是由（ ）吸收冲击能。
A.压溃管 B.橡胶垫缓冲装置 C.过载保护装置 D.防爬器 [判断题]我国个人所得税采用综合所得税制( )
A.正确 B.错误 [判断题]中央和本地ATS均显示故障时，按电话联系法组织。
A.正确 B.错误 我来回答: 提交
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