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 goes for a walk in a park in Washington. He is tired, so he sits down on a bench(长凳). A young person is standing on the other side of the pond(池塘). "Excuse me," the old man says to the person next to him on the bench, "Do you see the person with the red trousers and long hair? Is it a boy or a girl?"
"A girl," says the young person. "She is my daughter."
"Oh," the old man says quickly, "I am sorry, but I didn't know that you were her mother."
"I'm not," says the young person. "I'm her father."