For many years scientists have said that the earth is getting warmer. Now they have found something new-hot cities! In the southern US, they have found that cities become very hot in summer. For example, the city of Atlanta in Georgia has roof(屋顶) temperature of up to 50^oC while it is 27℃ in the streets! At night, the outside of buildings stays so hot that the heat of the city causes storms over the city!
China also has the same kind of problems. Every year more farmland is used for factories or offices. More housing is needed, too. As people become richer, they buy more cars. New roads are needed and new car parks are built in the city centers. This all makes cities hotter.
It isn’t easy to change the situation. City planners say that we should plant more trees in the middle of cities. Every new street should have trees on both sides, they say. Trees make the temperature lower, so we should have more trees in our parks and squares. We should also paint our roofs white. If we do this, they do not become so hot. Every roof in a hot and sunny country should have solar(太阳的) roof panels. The electricity from these can be used to run the air conditioners (空调)in the buildings.
People continue to cut down forests around the cities. This makes the problem worse. Cities are growing faster and faster. By the year 2025, four fifths(五分之四) of the population will be living in cities. If we go on like this, there will not be enough farmland to feed everyone in the world
The scientists have found       .

A．cities become very hot in summer

B．Atlanta is the hottest city in America

C．there are not as many storms as before

D．it is not as hot on the roof as in the street

The way to make the city cooler is to       .

A．plant more trees

B．try to use air conditioners more

C．build more parks and squares

D．paint the roofs of all the white buildings

What will probably happen in the future according to the fourth paragraph(段落)?

A．Cities won’t grow very fast

B．We will not have enough food

C．Most people will move to the countryside

D．People will plant more trees outside the cities

What is the best title(题目)for the passage?

A．More Farmland Is Needed

B．Trees Make Cities Cooler

C．Cities Are Getting Hotter

D．Scientists Are Worried About Storms