a year or two 与 one or two years有何区别

a year or two 与 one or two years有何区别 是one or two year还是one or two years a year or two 还是one year or two two-year-old 与two years old有何区别 one year or two one or two year 的意思 for two or one year(years)哪个对,why a day or two 与 one day or two 的区别? in a day or two与in one day or two的区别? a word or two ,one or two words 有什么区别 a two-day holiday 与in two years' time有何区别? one or two in one or two