A、It’s Columbus’ pure luck. B、It proves that the earth is not round. C、It enriched the American people. D、It’s one of the bigges

When people succeed, it is because of hard work, but luck has a lot to do with it, too. Success without some luck is almost impossible. The French emperor Napoleon said of one of his generals, "I know he’s good. But is he lucky?" Napoleon knew that all the hard work and talent in the world can’t make up for bad luck. However, hard work can invite good luck. When it comes to success, luck can mean being in the right place to meet someone, or having the right skills to get a job done. It might mean turning down an offer and then having a better offer come along. Nothing can replace hard work, but working hard also means you’re preparing yourself opportunity. Opportunity very often depends on luck. How many of the great inventions and discoveries came about through a lucky mistake or a lucky chance? One of the biggest lucky mistakes in history is Columbus’ socalled discovery of America. He enriched his sponsors and changed history, but he was really looking for India. However, Columbus’ chance discovery wasn’t pure luck. It was backed up by years of studying and calculating. He worked hard to prove his theory that the world was round. People who work hard help make their own luck by being ready when opportunity knocks. When it comes to success, hard work and luck are always hand in hand.
Questions 19 to 21 are based on the passage you have just heard.
19. What does the example of Napoleon tell us?
20. How should you understand "opportunity"?
21. What does the Columbus’ discovery of America suggest?