A César award winning documentary about a high school in Beijing where a student throws a ball in the direction of the teacher who had just asked them to stop playing. The class then meets to discuss this problem.

以北京第31中学发生的一次学生踢足球从老师头上飞过的偶然事件，师生之间所展开的一次激烈的讨论构成全片，反映了当时中国的学校这个意识形态机构所具有的民主与自由。本片获1977年凯撒奖最佳纪录短片。