with the development of society,people become more and more rich.as a consequence,an incressing number of people have cars.up to now,there are 3 milliion cars in bejing,206 of which are private cars.another 421000 new drivers added to the drivers last year.now the total number of driver is 4.23million.it is less safe to drive in cities,now that there are always more cars and people in cities.so i want to ask every driver including those who want to buy cars a question:shouldn't we ,for the sake of we humanbeings,as well as the blue and clear sky,drive provate cars less and less