a day's work a-day-work区别 急求!

a day's work 是正确的表达== a day's job
a-day-work是错误的表达
one-day work是正确的表达== a one-day job
a day-long job是正确的表达
再问： one-day work在意思上与a day's work有什么区别吗？two years old与two-year-old是不是一个意思呢？
再答： 1 one-day work-----只做一天的工作（工作的限期只有一天== the work lasts only one day ） a day's work-----（在一天裏面做的工作（量）） 2 She is two years old. she is a girl .== she is a two-year-old girl .