In recent years, with the improvement of life condition, more and more families have private cars. people think it's convenient to go everywhere in their own cars. They donn need to spend too much time waiting buses. Also owning a car makes others think the person is very rich. A s the saying goes, "A coin has two sides." On the one hand, the private cars provide convenience for our lives. People can drive the cars getting around the city easily. On the other hand, with the sharp increase of private cars, the air pollution becomes worse; the traffic jam is more serious; the road accidents more frequently occur. Moreover, it is hard to find a place to park the car and it is costly too. So, if possible, take a walk instead of a drive.