Uses of One and Ones

Concept 1

When it is clear from the context what we are talking about, then:
We can use the pronoun ‘one’ instead of repeating a singular countable noun.
We can use the pronoun ‘ones’ instead of repeating a plural countable noun

‘Is this your car?’ ‘No, mine’s the white one.’ (one = car)
People who drink aren’t the only ones vulnerable to liver failure. (ones = people)

One – singular; Ones – plural

These chairs are good but those one are excellent. (incorrect)
These chairs are good but those ones are excellent. (correct)

We don’t use ‘one/ones’ in place of an uncountable noun. We rather use some, any or nothing at all.

If you require any more paper, they will bring you one. (incorrect – we cannot use one/ones for uncountable noun paper)
If you require any more paper, they will bring you some. (correct)

We asked for water, but they did not had one. (incorrect – we cannot use one/ones for uncountable noun water)
We asked for water, but they did not had any. (correct)

Concept 2

We replace:

a/an + adjective + singular countable noun → a/an + adjective + one

some + adjective + plural countable noun → some + adjective + ones

My shirt is dirty. I will get a clean one. (a clean one = a clean shirt)
These fruits have gone bad. Let’s buy some fresh ones. (some fresh ones = some fresh fruits)

‘another’ is basically a merger of two words – an + other

I have seen some bad reviews of this hotel, so we should rather look for another one. (another one = another hotel)

Concept 3: Ones + Specific Information

If we are using ‘ones’, then we must provide some extra information, i.e. we can’t use ‘ones’ without additional information. We need to specify which ‘ones’ we mean. For example, big ones, ones with red flowers.

If we have no other information to offer, then we use ‘some’, instead of ‘ones’.

Compare:

We need to buy new sheets. Let us buy ones. (incorrect)
We need to buy new sheets. Let us buy saffron ones this time. (correct)
We need to buy new sheets. Let us buy ones with stars on this time. (correct)
We need to buy new sheets. Let us buy some. (correct)

Concept 4: Difference between one’s / ones / once

Do not use one’s in place of ones and vice-versa.

Let’s see the difference between ones, one’s and once.

One’s – it’s a possessive adjective, used to show possession
Ones – it’s an indefinite pronoun, plural of ‘one’
Once – an adverb, that means - one time

How successful a person will be in life depends on ones ability to cope with failures. (incorrect)
How successful a person will be in life depends on one’s ability to cope with failures. (correct; one’s ability – the ability that one has)

We can use anyone’s instead of one’s, without changing the meaning of a sentence. For example, anyone’s ability to cope with failures.

One’s bitten twice shy. (incorrect)
Once bitten twice shy. (correct; once adverb)

We can use ‘one time’ instead of the adverb ‘once’, without changing the meaning of a sentence. For example, One time bitten, twice shy.

Concept 5: Two uses of One’s

One’s may mean two things:

one’s as a possessive adjective, used to show possession
one’s as a contraction of ‘one is’

No one’s listening to you. (correct; here one’s just means ‘one is’; it Is not showing possession)
No one is listening to you. (correct)

That gift is for your brother. This one’s for you. (correct; here one’s just means ‘one is’; it Is not showing possession)
That gift is for your brother. This one is for you. (correct)

Concept 6: One is Indefinite Pronoun

‘one’ is an indefinite pronoun, i.e. it refers to an indefinite thing.

So, we cannot use ‘one’ to refer to a definite person or thing, e.g. the bike, my car, or someone’s name (say Annie). In such cases, we will use ‘it’ instead of ‘one’.

Compare:
“I need a comb. Do you have one?” (a comb - indefinite thing, because any comb will do. He is not asking for a specific comb.)
“The air conditioner stopped working. We should get it checked by a mechanic.” (the air conditioner – definite thing, because we know which air conditioner we are talking about)

So, the difference between ‘one” and ‘it’ is somewhat like indefinite article ‘a/an’ and definite article ‘the’. We use ‘a/an’ for things that are indefinite or not specified, and ‘the’ for something or someone definite/specific. As you would have noticed in the examples given above - a comb, The air conditioner.

Concept 7: Pronoun for One

If ‘one’ is working as the subject in a sentence, then to refer to that subject we use:

Possessive pronoun - one’s and
Objective pronoun – oneself

One should do one’s duty oneself.
One should keep one’s promise.

One must love his country. (incorrect)
One must love one’s country. (correct)

When not to use One/Ones

We don’t use one/ones in the following cases:

We don’t use ‘one/ones’ after ‘a’. So, we drop ‘a’.

Have you got any lemon? I need a one for a cocktail I am serving. (incorrect)
Have you got any lemon? I need one for a cocktail I am serving. (correct)

We don’t use ‘one/ones’ after nouns, which are used as adjectives.

Generally I keep the tickets in my shirt pocket, but that day I put them in my jeans one. (incorrect)
Generally I keep the tickets in my shirt pocket, but that day I put them in my jeans pocket. (correct)
We prefer Possessive pronouns (mine, yours, hers, etc.), rather than Personal pronouns (my, your, her, etc.) + one/ones.

I would really like to gift you a necklace like hers.

But we often do use Personal pronoun + one/ones in informal speech.

When we must use One/Ones

We must use one/ones in the following cases:

We must use one/ones after the, the only, the main, and every.

When you are wine tasting, you should mark the ones that taste funny.
After I got home, I found that every one was sleeping.
We must use one/ones after adjectives.

After a few months in lockdown, my shirts became so tight that I had to buy some new ones. (new - adjective)

However, while answering some question, we can often leave out ‘one/ones’ after colour adjectives. ‘Have you decided which school house to join?’ ‘Yes, I will probably join the blue (one).’

When we may or may not use One/Ones

We may or may not use one/ones in the following cases:

We may (or may not) leave out one/ones after ‘which’.

When we buy diamonds, we have no way of knowing which (ones) are original. (ones = diamonds)

We may (or may not) leave out one/ones after demonstrative pronouns (i.e. this, that, these, and those).

The last comedian was awesome, but this (one) is boring.

As per some experts, ‘those ones’ is incorrect. So, we should avoid using it, particularly in formal English.

Extra Books and Tools

If you prefer to learn via books, or want some good English Grammar books for reference purposes, you may read this article which enlists some of the books recommended by us.

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Last updated on Apr 8, 2023