A、Parents usually regard their children as grown-ups when they reach 13. B、The waiter usually places the bill in the middle of t

One evening several years ago, on a visit to my hometown, I sat with my wife, my son. and my parents at a restaurant. After a wonderful dinner, the waiter set the bill in the middle of the table. That’s when it happened: my father did not reach for it.
   Conversation continued. Finally I realized that I was supposed to pick up the bill and pay for the dinner! After hundreds of restaurant meals with my parents, after a lifetime of thinking of my father as the one who paid for our meals, it had all changed. I reached for the bill, and my view of myself was suddenly changed. I finally became an adult before my parents.
   Some people mark off their lives in years: I measure mine in small events. I did not become a young man at a particular age, like 13, but rather when a kid walked into the store where I worked and called me "mister. " He repeated it several times, looking straight at me. The realization came to me all of a sudden: Me! I was suddenly a mister.
   One day I bought a house. One day 1 became a father, and not too long after that I picked up the check for my father. These events are milestones of my life.
Questions 15 to 17 are based on the passage you have just heard.
15. What is the passage about?
16. In what way is the visit to his hometown significant to the speaker?
17. What can we infer from the passage?