Number Noun Adjectives

Rule 2.3: Do not pluralize number-noun adjectives that precede a singular, countable noun

He won the world championship twenty times.

Correct: He’s a twenty-time world champion boxer.
Incorrect: He’s twenty-times world champion boxer.

She’s a girl who is seven years old.

Correct: She’s a seven-year old girl.
Incorrect: She’s seven years old girl.

number noun adjectives

Exercise 16: Correct or incorrect?

Exercise 17: Choose the correct answer