2. 外语
  3. When early explorers sailed round the world, they use the stars to show【M1】________ them their position.Now drivers can use sate

When early explorers sailed round the world, they use the stars to show【M1】________ them their position.Now drivers can use sate

admin2021-03-09  56
问题       When early explorers sailed round the world, they use the stars to show【M1】________
them their position.Now drivers can use satellite navigation systems,【M2】________
satnavs for short, to tell them their route in exact the same way.The【M3】________
only difference is that satnavs use artificial stars-satellites.
      There are more then 20 satellites in the Global Positioning System【M4】________
（GPS） .The GPS satellites are about 20, 000 kilometers on the Earth.【M5】________
They have atomic clocks which tell the time to an accurate of one second【M6】________
in 300,000 years.
      The satnav compares the positions three or four satellites and works【M7】________
out exactly where it is.It does this several times by a second and is usually【M8】________
accurate to 20 meters anywhere in the world.But the satnav user need to【M9】________
give it accurate informations.Drivers sometimes get lost and end up in the【M10】________
wrong street, the wrong town, or even the wrong country.
【M5】
选项
答案on→above
解析
转载请注明原文地址:https://kaotiyun.com/show/O9AK777K
本试题收录于： C类竞赛（非英语专业本科）题库大学生英语竞赛（NECCS）分类
0

C类竞赛（非英语专业本科）

大学生英语竞赛（NECCS）

相关试题推荐
随机试题
最新回复(0)