3.He is a ______ child,that is ,he is a child of ________ A.three-years-old,three year old B.

问题描述:

3.He is a ______ child,that is ,he is a child of ________ A.three-years-old,three year old B.

分别填three-year-old,three years old.
有连字符的three-year-old是adj.三岁的
没有连字符的,要加s.