A、How to deal with car problems. B、How to write a thank-you letter. C、The kindheartedness of older people. D、The importance of e

Many years ago, when I was fresh out of school and working in Denver, I was driving to my parents’ home in Missouri for Christmas. I stopped at a gas station about 50 miles from Oklahoma City, where I was planning to stop and visit a friend. While I was standing in line at the cash register, I said hello to an older couple who were also paying for gas.
    I took off, but had gone only a few miles when black smoke poured from the back of my car. I stopped and wondered what I should do. A car pulled up behind me. It was the couple I had spoken to at the gas station. They said they would take me to my friend’s. We chatted on the way to the city, and when I got out of the car, the husband gave me his business card. I wrote him and his wife a thank-you note for helping me. Soon afterward I received a Christmas present from them. Their note that came with it said that helping me had made their holidays meaningful.
    Years later, I drove to a meeting in a nearby town in the morning. In the late afternoon I returned to my car and found that I’d left the lights on all day, and the battery was dead. Then I noticed that the Friendly Ford dealership — a shop selling cars was right next door. I walked over and found two salesmen in the showroom.
    "Just how friendly is Friendly Ford?" I asked and explained my trouble. They quickly drove a pickup truck to my car and started it. They would accept no payment. So when I got home I wrote them a note to say thanks. I received a letter back from one of the salesmen. "No one had ever taken the time to write to me and say thank you, and it meant a lot," he said.
    "Thank you" are two powerful words. They’re easy to say and mean so much.
Questions 29 to 31 are based on the passage you have just heard.
29. What is the purpose of the speaker to plan to stop at Oklahoma City?
30. What happened when the speaker found smoke coming out from the back of her car?
31. What does the speaker try to show by telling her own experiences?