two years old与two-year-old的用法区别，请不要用专业术语，请举例句，说白了就行

Question

如题所述

Answer 1

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

Answer 2

放在名词前时(就是作定语时），用two-year-old, 但要注意其中的名词必须用单数； 其他情况下用two years old, 可以以此类推。如:
He is a two-year-old child.
Her two-year-old daughter is in hospital.
I know the sixty-year-old man.
The child is two years old.
He is a child about two years old.
He is going on eighteen years old.
The baby is two months past two years old.