three-year与three-years的区别是什么?

three-year与three-years的区别是什么? three years old 与 three-year-old 的区别 three-year-old 与 three years old区别 three hundred years 与 three-hundred-year 的区别? after three year 还是 three year later three five year periods for year for year three three three Three Three three three three three-year-olds汉语意思 three-year's句式对吗? three year 用什么提问 Three year pain 还有esven year itch