Substitute word one/ones in English

The use of one/ones

We use one/ones instead of repeating a countable noun.

  • Singular: one
  • Plural: ones

John has three cars – a red car and two blue cars.
John has three cars – a red one and two blue ones.

Jack has five pens – two green pens and three yellow pens.
Jack has five pens – two green ones and three yellow ones

If you buy two bottles of water, you get a third bottle free.
If you buy two bottles of water, you get a third one free.