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Our city is a beautiful place. There are clean streets. On both sides of the streets, there are many tall trees. They make the city beautiful. There is a river through our city. The water is clean, but it was dirty before. Some people threw rubbish into the river. And there was a factory near the river. The smoke from the factory had a bad strong smell. But now people know that clean air and water are very important to their health, so they don't throw rubbish into the river any more. The factory doesn't release any dirty smoke now.