three-year-old boy 这样的前面用a还是an?两种我都看过..

At last the three-year-old boy was____(救） a three－year－old boy,可以说成a three years old many　thanks! 单句改错How slowly the three-year-old boy is to learn to talk three-year-old boy 这样的前面用a还是an?两种我都看过.. Are you (s　) three -year -old boy can play the piano? three-year-old 和 three years old 有什么区别 three years old 与 three-year-old 的区别 three -year-old 和 three years old有什么区别? three-year-old 与 three years old区别 Don’t complain to him.You know he is _____ boy.A.a three-years-old B.an eleven years oldC.an eleven-year-old D.only three year old 为啥? three-year-old triplet 的意思 a thirteen-year-old boy的中文翻译 a thirteen-year-old boy=什么? 11-year-old boy同义句转换 in the 1927, the plane wasa. three-meter-high b.three meters higha为什么不对?急!an eight-year-old boy不是和a同理的吗？ _____(a/an)1-year-old boy _____(a/an)8-year-old boy _____(a/an)11-year-old boy_____(a/an)13-year-old boy a twenty year old boy对还是a twenty years old boy对哪个等于 a twenty-year-old boy? 是a one-year-old boy还是an one-year-old boy