A lot of boys and girls in America are wearing the same clothes, and many of them have long hair, so it is often difficult to tell whether they are boys or girls. One day an old man went for a walk in a park in Washington, and when he was tired he sat down on a chair. A young person was standing on the other side of the take. "Excuse me," the old man said to the person next to him on the chair. "Do you see that person with red trousers and long hair Is it a girl or a boy" "A boy," said the neighbor, "he is my son." "Oh," the old man said quickly. "I am sorry, but I did not know that you were his mother." "I’m not." said the other person. "I am his father.\ The story happened in______.