Câu hỏi:

Read the passage and circle the best answer A, B or C.

If you live in a city, you will probably see many people, hear the noise of traffic, and smell the pollution from 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 country. Now many people are leaving the farms and moving into the cities. They are looking for better jobs. As a result, the cities are growing very quickly. Most cities are becoming more crowded. People are driving more cars, burning more fuel, using more water, eating more food, making more garbage, and producing more things in factories than ever before. Life in modern cities can bring many opportunities, but also many difficulties.

The authorities are trying to plan for a better future. They are building new roads, putting up new houses, looking for more water sources, and limiting growth in certain areas. But people are still crowding into the cities faster than the cities can take them. The cities are running out of space. There are no easy answers to this problem.

What is the main idea of the text?