卫生类职称英语[2018年职称英语《卫生类》概括大意练习(八)]

1、卫生类职称英语2018 年职称英语卫生类概括大意练习（ 8） 1.Children enjoy shouting at a high wall and hearing thesound e back to them.These sounds are called echoes Echoes have given us a number of valuable tools.（回声） .2.Echo sounding devices were early used in making maps ofthe ocean floor.Sounds or ultrasonic （超声的） sounds

2、make good tools for determining how deep the water is under ships.Sometimes echoes from ultrasonic distance findingdevices were prevented from working by fish swimming past or by the presence of large objects.So ultrasonic devices have been replaced by other tools.3.Radar is now a familiar tool.Like

3、 many others it was an unexpected discovery.It was first observed by two researchers, who were studying sound munication.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 thattheir signals were stopped by passing ships.Th

4、ey recognized the importance of this discovery at once.4.Allthiswas of course justa start,from which our presentradar has developed.The word radar, in fact, gets its namefrom the term radiodetection（检测） and ranging.Rangingis the term fordetectionof the distancebetween an objectandthe radar set.Today

5、, 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 fasterthan the speed limit, radar will show this clearly and the traffic police can take measures to stop him.6.Ap

6、ilotcannot flya plane by sightalone.Many conditionssuch as flying at night and landing in dense fog require thepilotto use radar.Human eyes are not very good at determiningspeeds of approaching objects,but radar can show the pilothowfast nearby planes are moving.23 Paragraph 224 Paragraph 325 Paragr

7、aph 426 Paragraph 5A Study of SoundB Highway PoliceC Working PrinciplesD Early Use of RadarE Useful ToolsF Discovery by Chance27 Echo-sounding devices were early used to28 Ultrasonic device were used to29 Police use radar on highways to30 Radar helps pilots toA detect nearby objectsB determine the depth of the ocean waterC decide how fast you dri