自考《英语(一)》试题练习:概括大意(3.21)
单选题
[概括大意]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 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.
The main idea of this paragraph is__________.
A.Study of Radar
B.Radar is now a familiar tool
C.Radar Working Principles
D.Radar was Discovered by Chance