1．In Chicago，a computerized system has been developed that controls（管理）traffic on the city's 235miles of seven expressways．Now one-a controller-can follow the movement of Chicago's traffic by looking at a set of lights．The system uses electric sensors（感應器） that are built into each expressway，every half a mile．Several times a second，the computer receives information from each sensor and translates it into green，yellow or red lights on a map in the control room．A green light means traffic is moving forty-five miles an hour，yellow means thirty to forty-five miles an hour，and red means heavy traffic-cars standing still or moving less than thirty miles an hour．
"See that red light near Austin Avenue？"the controller asked a visitor．"That's a repair truck fixing the road，and the traffic has to go around it．"At the Roosevelt Road entrance to the expressway，the light kept changing from green to red and back to green again．"A lot of trucks get on the expressway there，"the controller explained．"They can't speed up as fast as cars．"The sensors show immediately where an accident or a stopped car is blocking the traffic，and a truck is sent by radio to clear the road．The system has lowered the number of accidents by 18percent．There are now 1.4deaths on Chicago's expressway for each one hundred million miles traveled，while in other parts of the county there are 2.6．
Traffic experts say that the Chicago system is the"coming thing"．Systems like Chicago's are already in use on some expressways in Los Angeles and Houston．"Chicago has taken the lead，"said New York City's traffic director and he added，"Chicago's a good example．"
根據短文內容，選擇最佳答案，并在答題卡上按要求作答．
66．The passage is mainly aboutA on expressways in Chicago．
A．the traffic control system B．the movement of the traffic
C．the electric sensors D．the traffic lights
67．When the cars move under 30miles an hour，A on the map in the control room．
A．the red light appears B．the red light turns yellow
C．the yellow light appears D．the green light turns red
68．According to the passage，we may learnC．
A．some visitors are traveling on the expressway
B．there is no heavy traffic on Chicago's expressways
C．the traffic on Chicago's expressways is well managed
D．the number of accidents in the US has dropped by 18%
69．In Paragraph 2the underlined word"it"refers toD．
A．the red light B．the truck that needs repairing
C．the traffic D．the truck that is fixing the road
70．The writer writes the article mainly byB．
A．giving reasons and results B．giving examples and explaining them
C．describing what he thinks D．asking and answering questions．
分析 本文介紹了美國芝加哥用電腦系統如何管理城市的高速公路．
解答 66．A 大意理解題．根據文章第一段In Chicago，a computerized system has been developed that controls（管理）traffic on the city's 235miles of seven expressways大意可知這篇文章主要介紹了在芝加哥高速公路上的交通控制系統，故選A．
67．A 細節理解題．根據文章第一段A green light means traffic is moving forty-five miles an hour，yellow means thirty to forty-five miles an hour，and red means heavy traffic-cars standing still or moving less than thirty miles an hour．綠燈意味著交通每小時行駛四十五英里，黃色意味著每小時三十到四十五英里，紅色意味著重型交通車靜止不動或每小時移動不到三十英里．故選A，the red light appears．
68．C 理解推斷題．根據第二段和第三段的大意可知在芝加哥高速公路的交通被很好的管理．因此選C．
69．D 理解推斷題．根據上文That's a repair truck fixing the road那是修理公路的修理車，可知此處應該是：and the traffic has to go around it．車輛必須繞過它．可知此處it代替"the truck that is fixing the road"．故選D．
70．B 理解推斷題． 根據，"Chicago's a good example．"芝加哥是一個很好的例子．可知作者是通過舉例子講事實來寫這篇文章的．故選B．
點評 做題時要在理解好文意的基礎上，與題目有機的結合，從文章中找到相關細節性的句子與選項細細比對，進行選擇或推理判斷，選出符合文章內容的正確選項．做題注意靈活，有時可采用排除法或直選法確定出最終答案．
