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There were many apple trees in the garden. They were good friends. One day, an old tree was ill. There were many pests (害虫) in the tree. Leaves of the tree turned yellow. The old tree felt very sad and bad. His friends sent for a doctor to help him. At first, they sent for a pigeon (鸽子), but she had no idea about it. Then they sent for an oriole (黄鹂), and she couldn't do anything. Then they sent for a woodpecker. She was a good doctor. She made a hole in the tree and ate lots of pests. At last the old tree became better and better. The leaves turned greener and greener.