2014年5月29日,美国芝加哥的诺里奇伍德中学正在为即将毕业的学生举行毕业典礼。刚开始,毕业典礼按部就班进行。可是,就在校长发表毕业致辞的时候,台下开始有学生向空中扔帽子,并伴随着尖利的口哨声。接着,越来越多的学生把帽子扔向空中,使本来井然有序的毕业典礼乱成一团,校长的致辞也在学 On May 29, 2014, Norwich Middle School in Chicago, USA, is holding graduation ceremonies for graduating students. The beginning, graduation ceremony step by step. However, just as the principals delivered their graduation speeches, students from the audience began to throw hats into the air accompanied by sharp whistles. Then, more and more students threw hats into the air, messing up the otherwise well-organized graduation ceremony, and the president’s speech was learning