Mrs Walker has one son. His name is Harry. When he was four years old, he had a child's bicycle. It was red and white, and it had small wheels at its sides, so it always stayed up. Then Harry did not have a bicycle for a long time. Now he is twelve years old, and he wants a bicycle. Mrs Walker goes to work by car every day, and she takes Harry with her to his school, and brings him back when he finishes. His school is on one side of the town, and Mrs Walker's office is on the other side. "A lot of my friends have bicycles, and they ride to school on them," Harry said to his mother one day. "Their mothers don't need to take them to school and bring them home again." But his mother said to him, "Wait, Harry. Your father and I are going to buy you a nice bicycle soon." Then yesterday Mrs Walker stopped her car at a red light and looked at Harry. "Harry," she said to him, "your father and I are going to give you a bicycle next month, but first I'm going to ask you some questions. Now, look at those traffic lights. Do you know their meaning?" "Oh, yes, I do!" Harry answered happily. "Red is 'Stop', green is 'Go', and yellow is 'Go very quickly.' "