They're not due--the first one's not due until next Monday or Wednesday, so you can pick any three days to do it during that period of time.

第一份作业的截止日期是下周一或三,因此你可以任意选择三天来记录饮食

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

But it's only an effective vaccine in the context where you have people who can go to the doctor's office, or to an urgent care, some kind of medical facility, three times, reliably, at a specified period of time.

但为了保证接种效果,人们必须亲自去诊疗室,或者在急诊室里,使用一些医学设施辅助接种,还需要接种三次,它只在一段时间内有效

耶鲁公开课 - 生物医学工程探索课程节选

It's the one where you have to get three shots over a period of six months, and so you have to remember to go back, you get a first ba--you get a first shot, you have to remember to go back after a month and get a second shot, you have to go back after six months and get a third shot.

这种疫苗需要在六个月里注射三次,所以你要记得再去,你第一次,你第一次注射后,你要记得一个月后再去注射第二次,六个月后,你还得再去注射第三次

耶鲁公开课 - 生物医学工程探索课程节选