Look at the topic headings below, marked A, B, C, D E, and F, and match them with the paragraphs in the text below. There is one extra heading which you don’t need to use.
　　Questions 1-5 are based on the following passage.
　　A.Multi-centre cities
　　B.The urban world in 2050
　　C.The widening poverty gap
　　D.Rapid increase of urban population
　　E.Endangered coastal cities
　　F.Growing of small cities
　　1 ______
　　In 1900, just 13 percent of the world’s people lived in cities. In 2008, the number passed 50 percent for the first time in history. By 2050, the number will be about 70 percent. The urban population in Asia and Africa will double, and there will be nearly 30 “megacities”—cities with more than 10 million people. So what will life be like for people in the cities of the future? Professor of human geography Ben Rhodes describes his vision of the urban world in 2050.
　　2 ______
　　Life in cities will be very different from what it is today. Energy, especially oil, will be very expensive; so many people will probably work at home, or have their workplaces close to where they live. There’ll be less traffic on the roads, and it’ll be easier for people to be close to their families. For these reasons cities won’t have just one centre where everyone goes to work and shop. Instead, we’ll probably see cities with many different centers.
　　3 ______
　　It will be difficult to provide enough water, gas and electricity for really big cities, so they will probably stop growing. Many people from the countryside will move to smaller cities of 500,000 people or less. Transport over long distances will be a lot more expensive than it is now, so people will have to use food and energy from the countryside around their cities. They will use local materials for building, and perhaps traditional styles of architecture too.
　　4 ______
　　The thing I really worry about is that energy may become too expensive for many people. In the end we might have two groups of people: a rich group which can afford energy and lives in clean, green areas, and a bigger, poorer group which can’t afford it and has to live in the more polluted parts of the city. This might lead to serious social problems.
　　5 ______
　　As we all know, cities near the sea will probably experience some extra problems. As temperatures around the world go up, sea levels will rise and many places will have problems with flooding. Some cities will be safe, some may even find that the change in the climate is good for them, but others will need help. We really need to start planning for this now.