A、Taking an AT course. B、Going to see a superior. C、Talking with Dr. Albert. D、Speaking out for themselves. A短文中提到，参加“自信心确立训练法”课

Have you ever been afraid to talk back when you are unfairly treated? Have you ever bought something just because the salesman talked you into it? Are you afraid to ask someone for a date?(17)Many people are afraid to assert themselves. Or. Robert Albert, author of Stand Up, Speak Out, and Talk Back, thinks it’s because their self-respect is now. "There is always a ’superior’ around—a parent, a teacher, a boss—who knows better." But Albeit and other scientists are doing something to help people assert themselves. They offer "Assertiveness Training" course.(18)In the AT course, people learn that they have a right to be themselves. They learn to speak out and feel good about doing so. They learn to be aggressive without hurting other people. In other way, learning to speak out is to overcome fear.(19)A group taking an AT course will help the timid person to lose his fear. But AT uses an even stronger motive—the need to share. The timid person speaks out in the group because he wants to tell how he feels.(20)Whether or not you speak out for yourself depends on your se1f-image. If someone you face is more important than you, you may start to doubt your own good sense. But why should you? AT says that you can get to feel good about yourself. And once you do, you can learn to speak out.
17. What is the problem the speaker mainly talks about?
18. Which of the following is done in an AT course?
19. What is suggested to the timid persons to overcome their problems?
20. Why are some people afraid to speak out for themselves?