Many people have cars in the city. But {#blank#}1{#/blank#} (污染) is a problem because of the cars. Nowadays some downtown(闹市区的) areas around the world don't have cars. These car-free zones(无车区) are areas for people, bicycles and {#blank#}2{#/blank#} (公共的) transportation only. Eight million people  {#blank#}3{#/blank#} (居住) in the center of London and another two million people go to work there every day. The downtown area is very {#blank#}4{#/blank#} (吵闹的) with hundreds of cars, buses and taxis, but there are {#blank#}5{#/blank#} (也) a lot of beautiful parks with free music concerts. Many people go there for a rest {#blank#}6{#/blank#} (在……之后) they get off work. Parts of Tokyo are always crowded with hundreds of people- but no cars! These modern car-free zones are {#blank#}7{#/blank#} (真正地) popular and people like shopping there. In the past, Bogota was polluted {#blank#}8{#/blank#} (因为) there were lots of cars and traffic. Now the downtown area is a car-free zone and the air is {#blank#}9{#/blank#}(干净的)! Many people don't have a car and half a million people take the bus to work. There are lots of stores. It's not {#blank#}10{#/blank#}(昂贵的).