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(加油站) 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(收款台), I said hello to an older couple（夫妇）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 into 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 wonderful.
    Years later, I drove to a meeting in a nearby town in the morning. In late afternoon I returned to my car and found that I'd left the lights on all day, and the battery（电池） 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 told them my trouble. They quickly drove a pickup truck (小货车) 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 him and say thank you, and it meant a lot, he said.
    "Thank you" - two powerful words. They're easy to say and mean so much.