A day's study and a day's work, the next sentence

study for one day, and take ten days off if you don't study for one day.

I'll give you a few pupils

study for one day, and take one day off if you don't study.

it is difficult to walk with one foot, but it is difficult to become a household with one person.

first-class, second-class, second-class, third-class, and third-class success.