9.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 to find the user's position(位置).It can find your position to within 20metres.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.
25.According to the passage,with the help of the GPS,peopleA.
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 spend the least time getting to another place
26.The underlined word"They"in paragraph 3meansD.
A.Receivers
B.GPS devices
C.satellites
D.Ground stations
27.The passage is mainly aboutB.
A.the history of the GPS
B.the introduction of the GPS
C.the shape of the GPS
D.the three parts of the GPS.
分析 短文主要介绍了卫星定位系统和工程和工作原理.
解答 25-27 A D B
25.A;细节理解题,根据It can find your position to within 20metres.A GPS cannot start your car,but at least you will know where you are.可知卫星定位系统能让你知道自己在哪里,故选A,不会在一个新的城市中迷失.
26.D;推测词义题,根据语境,其前一句The third part of the system is a network of ground stations.可知指的是地面接收站,故选D.
27.B;文章大意理解题,根据文章主要内容主要介绍了卫星定位系统和工程和工作原理,可知选B.
点评 阅读理解题通常从细节,文章主旨,推测词组大意几个方面考查学生对文章的理解,做题时注意找到文章出处,做到有理有据.