twoyearsold,two-yearold,twoyears'old有什么区别?哪个对那个错呀?如果错了给我说下这几个表示法区别和具体用法谢谢!

Question

two years old ,two-year old ,two years' old 有什么区别?哪个对那个错呀?如果错了给我说下这几个表示法区别和具体用法谢谢!

Answer 1

two years' old、two-year old 错了,two years old 对了.
two years old 只可以做 表语 意思是 两岁
如 I am two years old.
two-year-old 只可以做 定语 意思是 两岁的
如 I am a two-year-old boy.
但不可以互换