The volume oftraffic in many cities in the world today continues to expand.This causes manyproblems, including serious air pollution, lengthy（漫长的）delays, and the

greaterrisk__________ (51)accidents.Clearly,something must be done,but it is oftendifficult to_________(52)people to change their habits and leave their cars athome.

Onepossible__________(53)is to make it more expensive for people to use their carsby __________(54)charges for parking and__________(55)tougher fines for anyone

who_________(56) thelaw. In addition,drivers could be required to pay for using particular routesat different times of the day.This system,_________(57)as"roadpricing",is

already beingintroduced in a_________ (58)of cities,using a special electroniccard_________(59)to the windscreen of the car.

Another wayof__________(60)with the problem is to provide cheap parking onthe________(61)of the city,and strictly control the number of vehicles allowedinto the

centre.Drivers andtheir passengers then use a special bus service for the_________(62)stage oftheir journey.

Of course,the mostimportant_________(63)is to provide good public transport. However,to getpeople to_________(64)the comfort of their cars,public transport must be felt

to be reliable （可靠的）,convenient and comfortable , withfares _________( 65 ) at an acceptable level._________(51)

A.of

B.for

C.about

D.by