内容正文:
UNIT 2 课时跟踪检测(三) 阅读写作融会练
Ⅰ.阅读理解
A
In the distant past, our ancestors relied on stars to guide them on a clear night.Today, we have navigational (导航的) systems to help us find our way, the latest of which is the Beidou Navigation Satellite System (BDS).
The BDS is entirely built by Chinese engineers.With the launch of the last satellite from the Xichang Satellite Launch Center on June 23, the global network of 59 satellites has been completed.On July 31, Beidou started providing services covering our whole planet.
It's difficult to imagine the great influence those satellites have on our daily lives.When you unlock one of Hellobike's bicycles, you are using the BDS.“The intelligent lock on each bike receives Beidou satellite signals and sends positioning information to the data center which will help collect big data on the bikes and predict users' riding needs in advance according to the data,” Chu Yiqun, a manager of Hellobike mentioned.Users can also find shared bikes more accurately (精确地) thanks to Beidou's global positioning accuracy of 2.34 meters.
Beidou adopts a unique two-way communication system, including its ability to receive messages sent by people from areas with poor communication signals.Obviously this function isn't designed for users to chat online.Instead, it plays a role when disasters occur and communications are blocked.
After the Wenchuan Earthquake in 2008, all ground-based communication facilities were interrupted.Though the first generation of Beidou could only send 120 characters in a single message at that time, communication between affected areas and rescue centers was successful.Now, Beidou's messaging ability has been increased to 1, 200 Chinese characters in a single message.It is widely used in disaster alarms, automatic identification and information release.
As Sun Jiadong, former chief designer of the BDS said, “The_application_of_Beidou_is_only_limited_by_imagination.”
语篇解读:本文是一篇说明文。文章介绍了北斗导航卫星系统在我们生活中的应用。
1.What can we learn a