It was my first day back home since starting college. A lot had changed in the last year. Not with my hometown but with me. I had left as a 17-year-old boy and had now returned as an 18-year-old man. In the city, I was living on my own, had a part-time job and was studying. Even the government recognized I was an adult: I had a driver's license. So here I was, on my summer vacation, walking down the main street with my father, desperate for him to acknowledge how mature I was. When his recognition failed to appear, I took matters into my own hands. "Dad," I said casually, "I'm thirsty. Let's go for a beer." It was the first time I'd ever mentioned beer in front of my father, let alone ask him to drink one with me. He turned to me with a curious expression on his face. "A beer ? Well I guess you're old enough now. Let's go to Sailors' Bar. It's where my cousin Tom, your uncle, used to drink. You remember him, right?" I had only some vague  memories of my uncle. He was _ . We didn't talk about him much. "What ever happened to Uncle Tom, Dad? I haven't seen him in years," I said as we continued towards the bar. "Neither have I, unfortunately. He was a good kid once. But things changed," my father said sadly. As a boy, he explained, there had been no better-behaved boy than Tom. But after leaving school, he moved to the city and fell in with bad company. He started going out every night, drinking in nightclubs and playing cards. Soon he lost everything and had to beg his mum to pay his debts. She agreed on the condition he returned home. My dad took a deep breath and continued his tale. "Things settled down for a while. He married a lovely woman, gave up his bad habits. But it didn't last. He was soon back to his old ways. He couldn't resist. He was at Sailors' Bar almost every night. His poor mother died of grief and shame. His wife followed her soon after. "What ruined him was alcohol. He told me once, when a man begins drinking, he never knows where it'll end. 'So', Tom warned me, 'beware of your first drink!' "He went from bad to worse. Last year Tom sent me a letter saying he had been found guilty of stealing, and sent to prison for ten years." Dad finished talking just as we reached the front of Sailors' Bar. "Anyway, here we are. Let's go in," he said. But I understood. I put my arm around my father and said, "I'm not thirsty any more, Dad. Let's go home." In the story, the father told his son about Tom in order to   _  .
entertain the son while they walked to the bar convince the son of the harm caused by drinking recall an interesting period in the father's life warn the son to keep away from Tom