In many big cities of the world,the overuse of cars is thoug

In many big cities of the world,the overuse of cars is thought to be the major cause of air pollution.What will cars be l___1__ in the future?
Some experts think that today’s cars in trouble b__2____ they use too much petrol(汽油).They say the cars of the future will be much smaller.The car of tomorrow will be m___3___ without a motor or air conditioning.It will have no radio and no lights.Tomorrow’s car will be an o___4____ air car with no doors or windows.It needn’t have a pollution control system because it w____5___ use petrol.In fact,this new car will be pushed by the driver’s feet.Very few people will be illed in accidents,because the top s___6___ will be five miles per hour.However,we are also warned not to ask for pretty c___7___.Because the cars will come in grey only.
Other car experts do not hold the same idea.They are s___8___ that the future will be happier.They think that all our problems will soon be solved by car companies with the production of the Supercar.Tomorrow’s car will be bigger,faster and more comfortable than b___9____.The supercar will have four rooms,TVs,running water,heat,air conditioning and maybe a swimming pool.Large families will travel on l___10____ trips comfortably.If petrol is in short supply,the supercar will run on water.