（1）Many big cities like London or Beijing become very "foggy" these days．

（2）The "fog is actually a problem that caused by air pollution．

（3）The air in London has become cleaner since nobody was allowed to buy coal．

（4）The air pollution from big factories mainly causes "fog " problem in China．

（5）China can solve the air pollution problem as easily as London．

（6）If people pay attention to the problem，there will be no more air pollution in China．