If you wish to change sections, you may do so only with permission of the subject administrators because it's very important that those sections be kept at a small population.

如果你们想要改时间，你只能在课程管理主任允许,的情况下这样做,因为让课程的人数保持在比较少的水平,是很重要的。

麻省理工公开课 - 固态化学导论课程节选