He is a boy.A. ten-years-oldB. ten-year-oldC. ten years oldD. ten year old

问题补充：

He is a boy.

A. ten-years-old

B. ten-year-old

C. ten years old

D. ten year old

答案：

A. ten-years-old

(答案→)B. ten-year-old

C. ten years old

D. ten year old

解析：句意：他是一个10岁的男孩子。ten-year-old十岁的，为形容词，后接名词，连词符号中间不用复数形式，故选B