a 15-year-old b 15-years-old c15-year-olds d15 y
问题描述：
a 15-year-old b 15-years-old c15-year-olds d15 y
a 15-year-old b 15-years-old c15-year-olds d15 years old he is 40years old and he is 25 years older than his son.he has a boy选哪个
答
选A,15-year-old意思为十五岁大的,有连字符,它不用变复数的