英语任务型阅读Now cities are full of cars. Some families even have

Now cities are full of cars. Some families even have two or more cars Parking is a great problem, and so is the traffic in around the cities. Something will have to be done to change it.
  What will the cars of tomorrow be like?
  Little cares may some day take the place of today's big cars.If everyone drives little cars in the future, there will be less pollution in the aie. there will also be more space for parking cars in cities, and the streets will be less crowded. Three little cars can fit in the space now needed for one car of the usual size.
  the little cars of the future will be fine for getting around a city, but they will not be yseful fir long trios. If big cars are still used along with the small ones, two sets of roads will be needed in future. Some roads will be used for the big, fast cars, and other roads will be needed for the slower small ones.

根据短文内容,完成下列各题.

1. In cities,______ is a big problem for those people who have cars.

2. In the ______,small cars will cost much less to own and to drive.

3. A small car's size of tomorrow may be ______ third of today's one cars usual size.

4. If people drive small cars ______ of the big ones,there will be less air pollution.

5. Two sets of roads will be built for the fast big cars and the ______ small ones.