If you live in a city, you probably see many people, hear the (1)__________________of traffic, and smell the pollution (2)__________________cars and factories.

    We are entering a new time in (3)_________________ history of the world. Before this, most (4)__________________were farmers. They lived in the country. Now many people are (5)__________________ the farms and moving into the cities. They are looking for better jobs. The cities are growing very quickly. Most cities are very crowded. People are driving more cars, burning more fuel, (6)___________________more water, eating more food, making more garbage, and producing more things in factories than (7)_________________ before. Life is becoming difficult.

    Some governments are trying to plan for the future. They are building new roads, putting (8) _________________new houses, looking for more water, and limiting growth in certain areas. Still, city planners are getting worried. People are crowding into the cities (9) ______________ than cities can take them. The cities are running out (10) ____________________rooms. What is the answer to this problem?