Possible Duplicate:
Adjective Pluralization
- He's a fifty-year-old man.
- He's fifty years old.
I'm fine with the first of these two sentences, in which "fifty-year-old" is a compound adjective.
In the second sentence, is "fifty years old" also a compound adjective? If not, is "fifty" an adjective modified by "years old"? I can't work it out!
