Fill each blank with a suitable word to complete the passage. If you live in a city, you will probably see many people, hear the noise of traffic, and smell the pollution (1)____________ cars and factories. We are living in a new era in the history of the world. Before this, most people were farmers. They lived in small communities in the (2)____________. Now many people are leaving the farms and moving into the cities. They are looking for (3)____________ jobs. As a result, the cities are growing very quickly. Most cities are becoming more (4)____________. People are driving more cars, burning more fuel, using more water, eating more food, making more garbage, and (5)____________ more things in factories than ever before. Life in modern cities can bring many opportunities, but also I many difficulties. The authorities are trying to plan for a better future. They are building new roads, putting (6) ____________ new houses, looking for more water sources, and limiting growth in certain areas. But people are still crowding into the cities faster (7)____________ the cities can take them. The cities are (8)____________ out of space. There are no easy answers to this problem.