问一下seven-years-old和seven years old有什么区别!
问题描述：
问一下seven-years-old和seven years old有什么区别!
答
1、seven-year-old作定语，其中year为单数形式；
He is a seven-year-old boy.
2、seven years old作表语，其中year为复数形式；
The boy is seven years old.
答
正确的应该是seven-year-old ,两个都是一个意思,没有区别.前者记得去掉year的s