单项选择题

Commuting to work in Chicago is no (47)________, for the roads there are even more crowded than in San Francisco. But here is how the city of Chicago is handling the problem. "We don’’t have rush hours any more," said Charles M. Mclean, who runs the nation’’s busiest road. " We have rush periods, and they keep (48)________ longer and longer. " In Chicago, a (49)________ system has been developed that controls on the city’’s seven expressways. Now, one man—a controller can (50)________ the movement of Chicago’’s traffic by looking at a set of lights. The system uses electronic sensors that are built into each expressway, half a mile apart. Several times a second, the computer (51)________ information from each sensor and translates it into green, yellow or red lights on a map in the control room. "See that red light near Austin Avenue" the controller asked a visitor, "That’’s a repair truck (52)________ the road, and the traffic has to go around it. " At the Roosevelt "Road entrance to the expressway, the light kept (53)________ 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 in no time where an accident or a stopped car is blocking traffic, and a truck is sent by radio to clear the road. The system has lowered the (54)________ of accidents by percent 18. There are now 1.4 deaths on Chicago’’s expressways for each one hundred million miles traveled, while in other parts of the country 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 (55)________ the lead," says New York City’’s transportation director; and he adds, "we are (56)________" WORD BANK A. pleasure B. race C. getting D. receive E. blocking F. computerized G. changing H. percentage I. after J. taken K. pleasant L. accepts M. ratio N. flashing O. behind