职称英语考试

试题来源：职称英语模拟题-卫生类-概括大意
【单选题】

1.Children enjoy shouting at a high wall and hearing the sound come back to them.These sounds are called echoes (回声). Echoes have givenus a number of valuable tools.

2.Echo sounding devices were early used in making maps of the ocean floor. Soundsor ultrasonic (超声的) sounds make good tools fordetermining how deep the water is under ships. Sometimes echoes from ultrasonicdistance finding devices were prevented from working by fish swimming past orby the presence of large objects. So ultrasonic devices have been replaced byother tools.

3.Radar is now a familiar tool. Like many others it was an unexpected discovery.It was first observed by two researchers， who werestudying sound communication. They were sending signals from a station on oneside of a river in Washington，

DIC.to a vehicle across the river. They discovered that their signals were stoppedby passing ships. They recognized the importance of this discovery at once.

4.All this was of course just a start， from which ourpresent radar has developed. The word "radar，"in fact， gets its name from the term "radiodetection (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 aperson in an automobile is driving faster than the speed limit， radar will show this clearly and the traffic police can takemeasures to stop him.

6.A pilot cannot fly a plane by sight alone. Many conditions such as flying atnight and landing in dense fog require the pilot to use radar. Human eyes arenot very good at determining speeds of approaching objects， but radar can show the pilot how fast nearby planes are moving.

23Paragraph 2

24Paragraph 3

25Paragraph 4

26Paragraph 5

AStudy of Sound

BHighway Police

CWorking Principles

DEarly Use of "Radar"

EUseful Tools

FDiscovery by Chance

27Echo-sounding devices were early used to

28Ultrasonic device were used to

29Police use radar on highways to

30Radar helps pilots to

Adetect nearby objects

Bdetermine the depth of the ocean water

Cdecide how fast you drive

Dstop passing ships

Emap the ocean floor

Fobserve water flow

网考网参考答案：D、F、C、B、E、B、C、A
大数据分析：根据网考网与考试题库的统计分析，该试题：
28%的考友选择了A选项
71%的考友选择了B选项
0%的考友选择了C选项
0%的考友选择了D选项
0%的考友选择了E选项
1%的考友选择了F选项
考友解析与评论：
 · 为什么选这个，有没有大神解答一下
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