A、A university instructor. B、A teaching assistant. C、A Ph. D. Student. D、A psychiatrist. A题目问的是DaneI Kindlon是做什么的。由定位句可知，他是哈佛公共卫

Discipline—or, to use today’ s more popular phrase, setting limits—takes on a whole new meaning when your child hits adolescence. " When kids are young and do something unsafe, parents have no trouble saying no," says Daniel Kindlon, Ph. D. , assistant professor of child psychology at the Harvard School of Public Health, who has two daughters, 15 and 12. "You don’t care that your two-year-old cries if you don’ t let him put the fork in the toaster. But saying yes to your teen can almost become a reflex, because you so desperately want to avoid conflict. " New research confirms what parents have known all along: adolescents simply lack the ability to make smart decisions consistently. For example, peer relationships—which are so important to teenagers—can easily overwhelm the need to be safe. Scientists have discovered that this has to do with the way the human brain grows. During the teen years, the brain develops rapidly, but some areas mature much earlier than others.
    Q19: What does Daniel Kindlon do?
    Q20: According to Kindlon, how do parents usually respond to their teens’ requests?
    Q21: Why are adolescents not able to make smart decisions consistently, according to scientists?