A、8 years. B、20 years. C、16 years. D、30 years. B细节题。短文中Ethbell明确说明，她在高中教授少数民族学生英语和喜剧，教了20年(for 20 years)，由此可知答案为B)。

After retiring from 30 years of teaching, Ethbell Pepper could easily have decided to sit back and relax and enjoy a peaceful retirement. But that kind of life is not for Ethbell Pepper. "I just wanted to do something different. If you are going to participate in life, do it. Don’t just sit down and look out the window," she says.[22]At 68, she decided to become one of the pioneer participants in a programme at the University me of California. The programme offers campus housing and classes to people over sixty. She enrolled in a class called Human Relationships and Diverse Society. "I taught my minority students in my English and drama classes in high school for 20 years. But in this course, I found out a lot about other cultures I didn’t know then.[25]One of the most important lessons that I’m learning is to perceive, not to judge."[24]Older adults can add to the educational resources of university by bringing with them a lot of valuable experience. Their presence on campus helps break some long-held beliefs of aging. Young students may have fears of growing older. But that kind of fear can be reduced as they see that older people can be active, healthy, and continue to contribute to society. The younger students can begin to see aging as a natural part of living.
22. What did Ethbell do when she was 68?
23. How long did Ethbell teach minority students?
24. What do elderly people do to the university?
25. What’s the most important lesson Ethbell is learning?