john is honest and helpful.we all like the boy _____

题目

john is honest and helpful.we all like the boy _____
a of ten years old b ten-year-old c at ten old d of age of ten
答案是A为什么啊

答案

of ten years old 介词短语作后置定语,修饰the boy .B选项应放在boy之前,即the ten-year-old boy .C选项 老实说我没见过那种用法,所以基本排除.D选项应把第一个of 改为at ,是固定搭配