阅读短文，从各题所给的选项中，选择最佳选项．

Imagine the situation．You are driving along a desert or on a mountain．Then your car breaks down．You have no idea where you are．What should we do？Well，next time take a GPS with you．It is a device（设备） which uses satellites to find the user's position．It can find your position within 20meters．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 it 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（绕） the Earth．The receiver contacts（联络） at least four of the satellites and calculates（计算） its position．The third part of the system is a net work of ground stations．They are all over the world．They control the satellites and make sure theyare 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．

66．According to the passage，with the help of the GPS，people 　　．

A．	can't be lost in a new city
B．	can't find their way in different countries
C．	can learn about the culture of an unknown place
D．	can find their position within 2000kilometers

67．We can learn from the passage that 　　．

A．	there are three parts to the GPS
B．	a GPS can't be put into the watch
C．	a GPS can help you start your car
D．	the GPS devices are becoming more and more expensive

68．The underlined word" they"in paragraph 3means" 　　"．

A．	receivers
B．	GPS devices
C．	a network of ground stations
D．	satellites

69．The passage is mainly about 　．

A．	the history of the GPS
B．	the introduction of the GPS
C．	the shape of the GPS
D．	the price of the GPS

70．what can we infer（推断） from the passage？ 　　

A．	All GPS devices have electronic maps．
B．	People all over the world 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．

科目 英语   题型 阅读填空   难度 中等

知识点： 综合型 科普知识类阅读