第一部分 阅读理解
第一节（共15小题；每小题2分，满分30分）
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Have you ever done something that was really dangerous just because you thought it was safe? Maybe you did a dangerous trick (杂耍动作) on your bicycle or skateboard because you were wearing a helmet (头盔） and thought you couldn't get hurt. The psychology (心理) of this sort of behavior is called the Peltzman Effect, named after Sam Peltzman, professor of economics at the University of Chicago. Peltzman believes that those moments when people think they are the safest are the times when they act most dangerously.
