Mrs. White has a son.    The young man begins (开始)to work in a post office in a city this autumn. He asks his mother to visit the city. The old woman is happy and catches a train.     but she doesn’t know where the post office is. She begins to look for it, but she can’t find it. At a bus stop she asks an old man, “Excuse me, sir. How can I get to the post office?”
 says the o1d man. “Which one do you want?”
The old woman gives Sam’s letter to him and the old man says, “Walk along this street and take the fourth turning on the left.   .”
Mrs. White thanks the old man and soon finds her son. They’re very happy. A week later the woman goes to the zoo.     But after that she can’t find the way to the post office again. At the same bus stop she meets the same old man and she asks the same question again.
“Oh dear!” the old man calls out. “Are you still looking for your son?”

A. His name is Sam White. B. She sees all kinds of animals. C. Soon she gets to the city. D. “We have about forty post offices in the city.” E. You can find the library easily. F. The pay phone is across from the hospital. G. His post office is just there.