two years and a half 还是two year and a half

two years and a half 还是two year and a half two and a half some two-and-a-half years and two novels later,^^^^^^ two years and a half=two and a half years吗? two years and a half 或者two and a half years - years ago ,I came to the USA.Two and a half Two and half a two hours and a half He has been here for two and a half year half的用法是 one and a half years 还是one and a half year?half具体的用 one and a half 后加year 还是years three years and half a year 请问“两个半小时”是“two and a half hour”还是“tow and a half hours”?