7．閱讀短文，從各題所給的選項中，選擇最佳選項．
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（設(shè)備） 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（繞） the Earth．The receiver contacts（聯(lián)絡(luò)） at least four of the satellites and calculates（計算） 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 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（精確的）．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，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 find their position within 2000kilometers
67．We can learn from the passage thatA．
A．there are three parts to the GPS
B．a(chǎn) GPS can't be put into the watch
C．a(chǎn) 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"D"．
A．receiversB．GPS devices
C．a(chǎn) network of ground stationsD．satellites
69．The passage is mainly aboutB．
A．the history of the GPSB．the introduction of the GPS
C．the shape of the GPSD．the price of the GPS
70．what can we infer（推斷） from the passage？D．
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．
分析 這篇短文主要介紹了衛(wèi)星定位系統(tǒng)的工程及工作原理．衛(wèi)星定位系統(tǒng)能讓你知道自己在哪兒，不會在新城市中迷路．衛(wèi)星定位系統(tǒng)有三個部分，第一部分是接收機．第二部分是一組圍繞地球衛(wèi)星接收器觸點．第三個部分的系統(tǒng)是一個地面站網(wǎng)絡(luò)．衛(wèi)星定位系統(tǒng)在日常生活中會像手機一樣普遍．
解答 答案：66．A 細(xì)節(jié)理解題． 根據(jù)第一段句子It can find your position within 20 meters．A GPS cannot start your car，but at least you will know where you are，它可以在20米內(nèi)找到你的位置．GPS無法啟動你的車，但至少你會知道你在哪里．可知衛(wèi)星定位系統(tǒng)能讓你知道自己在哪兒．不會在新城市中迷路．故選A．
67．A 細(xì)節(jié)理解題．根據(jù)第三段句子There are three parts to the Global Positioning System．全球定位系統(tǒng)有三個部分，可知衛(wèi)星定位系統(tǒng)有三個部分．故選A．
68．D 細(xì)節(jié)理解題．根據(jù)第三段句子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第三部分是一個地面站網(wǎng)絡(luò)，他們遍布世界各地，他們控制的衛(wèi)星，確保它們正常工作；可知這里they意為地面站；故選D．
69．B 主旨?xì)w納題．根據(jù)整篇文章內(nèi)容及其第二段句子GPS，which means Global Positioning System，is a small radio receiver全球定位系統(tǒng)（GPS），這意味著全球定位系統(tǒng)，是一種小型無線電接收機．可知這篇短文主要介紹了衛(wèi)星定位系統(tǒng)的工程及工作原理．即介紹衛(wèi)星定位系統(tǒng)．故選B．
70．D 細(xì)節(jié)理解題．根據(jù)最后一段句子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（精確）．可知衛(wèi)星定位系統(tǒng)在日常生活中會變得越來越普通．故選D．
點評 在通讀全文的基礎(chǔ)上，根據(jù)全文大意，展開邏輯思維，瞻前顧后，認(rèn)真觀察選項，仔細(xì)推敲，確定最佳答案．
