Mr. Green worked in the city, but he lived in the countryside and came to work by train every day. The station was next to his office, and Mr. Green always walked to his office from the station. He always went along the same street in the evening. Every evening, he passed a poor man with a dog near him. There was a piece of paper round the dog's neck, and the words "I AM BLIND" were on it.
Mr. Green was a good man and he always said a few words to the poor man and gave him a little money.
One day, Mr. Green had a lot of work in his office and was very late. The train would leave in a minute. So he didn't stop in front of the man and his dog. After he had passed, the poor man stood up quickly, ran after him and said, "You haven't given me anything today." Mr. Green stopped and said in surprise, "You are a blind man. How did you know that I passed?" The poor man said, "No, I'm not. My old dog is."