听力原文： Up to now, we have focused on the positive impact of the automobile on society in the United States. Today we'll look at some of the negative effects. A number of sociologists blame the automobiles for the decline of the downtown areas of the major cities. In 1950s and 1960s, the automobile made it possible to work in the cities and yet live in the suburbs many miles away. Shopping patterns changed, and instead of patronizing downtown stores, people in the suburbs went to large shopping malls built in open areas outside the city where everything was cheaper. Merchants in the city failed, and stores closed. Downtown shopping areas became deserted. In recent years, there has been a rebirth in a number of downtown areas, as suburbanites, especially young married couples, have moved into the city to avoid roads covered with the traffic between the suburbs and the cities every morning and evening. Now let's look at some slides that illustrate these trends. By the way, tomorrow I'll explain the effect of all these automobiles on the environment. For example, what happens to the atmosphere as a result of burning of gasoline and the depletion of natural resources like fossil fuels? (33)