Passage 3 Questions 11 to 15 are based on the following passage: I hear many parents complain that their teenage children are rebelling. I wish it were so. At your age you ought to be growing away from your parents. You should be learning to stand on your own feet. But take a good look at the present rebellion. It seems that teenagers are all taking the same way of showing that they disagree with their parents. Instead of striking out boldly on their own, most of them are holding one another's hands for reassurance (放心). They claim they want to dress as they please. But they all wear the same clothes. They set off in new directions in music. But they all end up listening to the same record. Their reason for thinking or acting in such a way is that the crowd is doing it. They have come out of their cocoon (茧) into a larger cocoon. (80) It has become harder and harder for a teenager to stand up against the popularity wave and to go his or her own way. Industry has firmly carved out a market for teenagers. These days every teenager can learn from the advertisements what a teenager should have and be. This is a great barrier for the teenager who wants to find his or her own path. But the barrier is worth climbing over. The path is worth following. You may want to listen to classical music instead of going to a party. You may want to collect rocks when everyone else is collecting records. You may have some thoughts that you don't care to share at once with your classmates. Well, go to it. Find yourself. Be yourself. Popularity will come—with the people who respect you for who you are. That's the only kind of popularity that really counts. 第11题：The author's purpose in writing this passage is to tell______.