Imagine the situation. You are driving along a desert or on a mountain. You have no idea w

Imagine the situation. You are driving along a desert or on a mountain. You have no idea where you are. You passed the last house two hours ago. Then your car breaks down. It is night and it is cold. You have no mobile phone. What do you do? Well, next time take a GPS with you. This invention may be able to help you. It is a device(装置) which uses satellites (卫星) to find the user’s position(位置). It can find your position to within 20 metres. A GPS cannot start your car, but at least you will know where you are.
GPS, which means Global Positioning System, is a small radio receiver. It looks like a mobile phone. You can hold it in your hand, or put in your pocket. It is sometimes put into a watch or a telephone. We also find GPS devices in cars, planes, or boats. Some of these devices have electronic maps, so you know where you are. For example, in a city they can tell you the name of the street.
There are three parts to the Global Positioning System. The first part is the receiver. You can hold it in your hand, or have it fixed into your car, plane, etc. The second part is a group of satellites orbiting the Earth. The receiver contacts at least four of the satellites and calculates(计算) its position. The third part of the system is a network of ground stations. They are all over the world. They control the satellites and make sure they are working well.
Some people think that in the future the GPS will be as common as the mobile. They are becoming cheaper and more and more accurate(精确的). There are also new uses for the GPS. Perhaps they will become like watches. Everyone will have one and you will never be lost again.
【小题1】According to the passage, with the help of the GPS, people .A．can’t be lost in a new cityB．can’t find their way in different countriesC．can learn about the culture of an unknown placeD．can spend the least time getting to another place【小题2】We can learn from the passage that .A．there are three parts to the GPSB．a GPS can’t be put into a watchC．a GPS can help you start your carD．the GPS are becoming more and more expensive【小题3】The underlined word “They” in paragraph 3 means “ ”.A．ReceiversB．GPS devicesC．SatellitesD．Ground stations【小题4】The passage is mainly about .A．the history of the GPSB．the introduction of the GPSC．the shape of the GPSD．the three parts of the GPS【小题5】What can we infer(推断) from the passage?A．All GPS devices have electronic maps.B．People in many countries will use the GPS for free.C．The receiver of the GPS contacts at least five of the satellites.D．The GPS will become more and more common in everyday life.A

(答案→)A 解析：短文大意：这篇短文主要介绍了卫星定位系统的工程及工作原理。【小题1】根据短文第一段It can find your position to within 20 metres. A GPS cannot start your car, but at least you will know where you are.描述，可知卫星定位系统能让你知道自己在哪儿。故选A，不会在新城市中迷路。【小题2】根据第三段There are three parts to the Global Positioning System.描述，可知卫星定位系统有三个部分。故选A。【小题3】联系下文The third part of the system is a network of ground stations.描述，可知指的是地面接收站。故选D。【小题4】这篇短文主要介绍了卫星定位系统的工程及工作原理。故选B，介绍卫星定位系统。【小题5】根据短文最后一段描述，可知卫星定位系统在日常生活中会变得越来越普通。故选D。

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