We use one (singular) and ones (plural) to avoid unnecessary repetition.

See those two girls? Helen is the tall one and Jane is the short one.
Which is your car, the red one or the blue one?
My trousers are torn. I need some new ones.
See those two girls? Helen is the one on the left.
Let’s look at the photographs. The ones you took in Paris.

We often use them after Which ... in questions:

You can borrow a book. Which one do you want?
There are lots of books here. Which ones are yours?




Of course we can. It depends on the situation or context. And, it is not appropriate for formal situations.

Dear teacher,

As per my understanding, in question 1, the correct question sentence should be "How old are your children?" instead of "How old are my children?" Am I correct? Thank you so much in advance!

Hello Leo Le,

It would be more common to hear 'How old are your children?', wouldn't it? However, 'How old are my children?' is quite possible as a rhetorical question, or a repeated question to check that a person understands.

Best wishes,


The LearnEnglish Team

With one and one's, what about the use of them in sentences as follows:

One rarely greets the Queen without bowing first.

It is unusual to bow to one's friend, however.

Hello John Murray,

'One's' is simply the possessive 's at the end of the pronoun.

'One' as a pronoun is used in a very formal style to mean 'a person'.

Best wishes,


The LearnEnglish Team

Hello Sir,
I have a question regarding comparatives actually, that are mentioned here.

In one sentence above, it is written:
Helen is the TALL one and Jane is the SHORT one (instead of taller and shorter)

and in a sentence in the exercise on this page, it is written:
The YOUNGER one is old and the OLDER one is seven (instead of young and old)

Please tell me why there is such discrepancy in these sentences.

Thank you

Hello adtyagrwl3,

In the first example both 'tall' and 'taller' are possible, and 'short' and 'shorter'. If we say 'tall' then we are simply describing a characteristic of Helen; if we say 'taller' then we are comparing her to someone else.

In the second example there is a similar choice. We can describe a general characteristic ('young') or compare the person with someone else ('younger').

Best wishes,


The LearnEnglish Team

Exercise...a perfect one

Should the sentence ‘I hope this holiday will be one to remember.’ be 'I hope this holiday will be one to be remembered.’? If both of them are right, could you please tell me the difference? Thank you very much indeed.