translation.en: You've given the lectures, so now what we do --" And this could happen in every classroom in America tomorrow -- "what I do is I assign the lectures for homework, and what used to be homework, I now have the students doing in the classroom."
translation.zh: 你给学生讲课，所以现在我们所做的是...." 没准这样的情形明天也会在美国的每间课室发生， “...我所做的就是分配视频讲座给学生， 这曾经是家庭作业， 但现在学生在教室做家庭作业”。