a four-year-old boy可以说成a four-year old boy

a four-year-old boy可以说成a four-year old boy 请问:是a four years old boy?还是a four year old boy?正确 They were surprised that a four-year-old boy should work out 帮忙翻译下my four year-old boy tried to start a mosh pit during n a three－year－old boy,可以说成a three years old he is a 6-year-old boy.可以说he is a 6 years old boy吗 帮忙把这句话准确幽默的翻译下my four year-old boy tried to start a mosh pit he is a 13-year-old boy a thirteen-year-old boy=什么? a thirteen-year-old boy的中文翻译 _____(a/an)1-year-old boy _____(a/an)8-year-old boy _____(a/ 为什么 a four-year-old boy中的year可以不加复数,而分数two-thirds中连字符后的third