One of the biggest accomplishments in sports in the last hundred years was the 4-minute mile. Running a mile in under 4 minutes was a huge barrier in sports. Once it was broken by one person, lots of athletes tried to break it too. For years, people thought that running a mile in less than 4 minutes was just  _ impossible. It was common knowledge that nobody on earth could physically run a mile in under 4 minutes. Professional runners had been trying for years, training to beat that time, but had failed every time. In 1952, a British man by the name of Roger Bannister set a goal for himself: to be the first person to run a mile in under 4 minutes. He trained intensely, and 2 years later, Bannister finally broke 4-minute barrier. And you know what? Soon after that, more and more people began to run the mile in under 4 minutes. New world records were set almost every year following Bannister's sub-4-minute-mile. Nowadays, even a high school student can reasonably run a 4-minute mile. In about 50 years, the 4-minute mile went from impossible to professional to amateur. But I guess I'm not really answering the question here: what on earth does this have to do with learning Japanese? When you have a goal in mind, mental barriers can be huge obstacles to overcome, and learning Japanese is no different. But if you're devoted enough and make your goal your top priority , you might be surprised at what you can do. Put everything else aside for a while, just go for it and see what you can achieve. After all, if somebody can accomplish something that people thought was physically impossible, then maybe learning Japanese isn't so hard after all. According to the passage, we can know that   _
all the high school students can run the mile in under 4 minutes high school students try to break records in the sports field learning Japanese is not difficult at all mental barriers are the biggest ones when achieving goals