提高听力同时，你还可以了解到美国历史上的一些重要事件。请感兴趣的你一听为快吧！
<注意>职称、节日、组织要大写
Students protested the war in Vietnam and President Johnson began peace negotiations. Long hair, rock and roll music and illegal drugs were visible symbols of the "counter-culture" thinking of some young people during this time. Americans became more concerned about pollution. The first Earth Day was designated in 1970. The Environmental Protection Agency was created. New laws cut down on pollution. American society was changing. Slowly, the United States was embracing its multicultural population.
学生抗议越南战争，约翰逊总统开始和平谈判。长头发，摇滚乐和非法毒品的“反文化”在此期间，成为一些青少年思想可见符号。美国人变得更关心污染。在1970年被指定为第一个地球日。环境保护署已创建。新的法律削减污染。美国社会正在发生变化。慢慢地，美国包含多元文化的人口。