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Many people have cars in the city．But pollution is a problem because of the （1） 　 　．Nowadays some downtown （市中心） areas around the world don't have cars．These car﹣free zones （无车区） are （2） 　 　for people，bicycles，and public transportation only．

Eight million people （3） 　 　in the center of London and another two million people go to work there every day．The downtown area is very（4） 　 　with hundreds of cars，buses，and taxis，but there are （5） 　 　a lot of beautiful parks with free music concert．At lunchtime，many people go there for a rest （6） 　 　they get off work．

Parts of Tokyo are always crowded with hundreds of people﹣but no cars! These modern car﹣free zones are （7） 　 　popular and people like shopping there．

In the past，Bogota was polluted because there （8） 　 　lots of cars and traffic．Now the downtown area is car﹣free zone and the air is （9） 　 　!Many people don't have a car and half a million people take the bus （10） 　 　．There are lots of stores．It's not expensive．