English for Today by Ganiu Abisoye Bamgbose (Dr GAB)
COMPOUND ADJECTIVES
I saw the ~ten years~ old boy sometime last week (non-standard).
I saw the ten-year-old boy sometime last week (standard).
The boy is ~ten year~ old (non-standard).
The boy is ten years old (standard).
Note that “ten-year-old,” in the first sentence, is a compound adjective that qualifies the noun “boy.” No part of this compound adjective should be pluralised, just like we do not pluralise conventional adjectives. “Ten years,” in the second sentence, is a noun phrase that precedes the adjective “old.”
I was around for the ~two days~ seminar (non-standard).
I was around for the two-day seminar (standard).
Again, no aspect of the compound adjective “two-day” should be pluralised.
GAB
