2.Echo sounding devices were early used in making maps of the ocean floor.Sounds or ultrasonic （超声的） sounds make good tools for determining how deep the water is under ships.Sometimes echoes from ultrasonic distance finding devices were prevented from working by fish swimming past or by the presence of large objects.So ultrasonic devices have been replaced by other tools.
3.Radar is now a familiar tool.Like many others it was an unexpected discovery.It was first observed by two researchers, who were studying sound communication.They were sending signals from a station on one side of a river in Washington,
D IC.to a vehicle across the river.They discovered that their signals were stopped by passing ships.They recognized the importance of this discovery at once.
4.All this was of course just a start, from which our present radar has developed.The word "radar," in fact, gets its name from the term "radio detection （检测） and ranging." "Ranging" is the term for detection of the distance between an object and the radar set.Today, in our scientific age, it would be difficult to manage without radar.
5.One of the many uses of radar is as a speed control device on highways.When a person in an automobile is driving faster than the speed limit, radar will show this clearly and the traffic police can take measures to stop him.
6.A pilot cannot fly a plane by sight alone.Many conditions such as flying at night and landing in dense fog require the pilot to use radar.Human eyes are not very good at determining speeds of approaching objects, but radar can show the pilot how fast nearby planes are moving.
23 Paragraph 2
24 Paragraph 3
25 Paragraph 4
26 Paragraph 5
A Study of Sound
B Highway Police
C Working Principles
D Early Use of "Radar"
E Useful Tools
F Discovery by Chance
27 Echo-sounding devices were early used to
28 Ultrasonic device were used to
29 Police use radar on highways to
30 Radar helps pilots to
A detect nearby objects
B determine the depth of the ocean water
C decide how fast you drive
D stop passing ships
E map the ocean floor
F observe water flow
[参考答案]
23.D 24.F 25.C 26.B 27.E 28.B 29.C 30.A
【2016年职称英语《卫生类》概括大意练习（8）】相关文章：
人教版七年级上册一单元作文：这就是我（14）_300字02-07
经典英语美文阅读翻译-时间的价值是多少02-07
出国旅游常用英语口语（问路篇）02-07
2025天津公务员考试行测题库：行测每日一练判断推理练习题4.2302-07
2016年7月10日托福写作真题预测02-07
高中英语作文：高中的记忆02-07
2017年小升初英语模拟试题（七十一）02-07
2019上半年初中英语教师资格证面试试讲真题【网友版】02-07
中考英语作文范文 外国友人说重庆变化很大02-07