If you don't make it to class, contact your TA, your recitation instructor, and you can take a makeup within a week of the time of original test.

如果你不能来上课，联系你们的助教，背诵课的老师，你可以在测试后那个礼拜内,找时间补回来。

麻省理工公开课 - 固态化学导论课程节选

Five hours is contact time. That's three hours here, and two hours with the recitation instructor.

联系时间是5个小时，这有三个小时，其余2小时是和背诵课的讲师。

麻省理工公开课 - 固态化学导论课程节选