自考《英语(一)》试题练习:概括大意(9.6)
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