"Please be quiet, class is about to start" 这句话来源于英语教学场景中，用来提醒学生课程即将开始，需要保持安静。
例句1: "Please be quiet, class is about to start" (请保持安静，课程即将开始)
例句2: "Can everyone please be quiet, we're about to begin the lecture" (大家都请安静，我们即将开始讲座)
例句3: "Shh, class is starting" (嘘，课程开始了)