1
The Indefinite Article A / An – One /Ones
A / An
We use a / an
We do not use a / an
 with singular countable nouns when we talk about
them in general
I want to buy a dress (any dress).
An orange contains vitamin C.
NOTE: Such a structure is less usual than the
structure with plural form of a noun.
Oranges contain vitamin C.

when we first mention something
A man booked into a hotel.

when we describe something
It was a lovely day.
This is a better photo.
It’s a big hotel.
BUT: there are special cases when we use a /
an with uncountable nouns:
The use of the indefinite article with an abstract
noun may be the result of the noun becoming
countable or may be a formal result of the use
of a descriptive attribute with almost any
abstract noun (exceptions are given below):
The critic who has not a practical knowledge of
technique is seldom able to say anything on the
subject of real value (Steinbeck).

when we want to say what someone’s job is
My sister is a scientist.
 with the verbs to be and to have (got)
Mary has a dog. It’s a German Shepherd.

with uncountable nouns or plural countable nouns.
We use some instead of a / an
We need some milk and some flour.
They bought some flowers.

 when we classify something
The play was a comedy.
The man’s disappearance was a mystery.


before Mr/Mrs/Miss/Ms when we refer to an unknown
person
A Mrs Jones called you this morning (a person that
we don’t know)

to show:
 a price in relation to weight (two pounds a kilo)
 distance in relation to speed (80 km an hour)
 frequency (twice a week)

after quite, such, what
It was such an easy test.
It was such a steep hill.
What an amazing day! (See Unit 89 from Oxford Practice
In formal writing and literary works the article
a/an may be used with some uncountable
abstract nouns to show an unusual or temporary
aspect of something. The indefinite article here
means: such, certain, special, peculiar.
The director spoke at the meeting today with an
enormous enthusiasm. (formal / literary style)


The article is usually absent after the
preposition ‘of’: a look of mild astonishment; a
kind of quiet thoughtfulness, etc.
Moreover, some abstract nouns are known not
to take an indefinite article even if there is a
descriptive attribute. The most undoubted words
in this group are: weather, news, information,
advice, progress, work, permission, music,
health, fun, luck.
This is very valuable work.
Grammar. Intermediate.)

With certain numerical expressions (esp. of quantity
and measurement): a couple (of), a dozen, half a
dozen, a score, a gross, a hundred, a thousand, a
million, a lot of, a great many (students), a great deal
of (coffee).
A / An / One
 We use a / an to refer to an unspecified thing with the meaning ‘any one’. We use one when we are counting, to
put emphasis on number.
He bought a tie (we are not talking about specific tie).
He bought one tie. (He didn’t buy two ties)

We use a / an or one with no difference in meaning when counting or measuring distance, weight, etc.
I paid a / one hundred of pounds for this bracelet.
I bought a / one carton of milk.
2

We use one with the words day, week, month, year, winter, morning, night, etc. or with a specific day or month
to say when something happened in narration.
One summer, the family decided to go to Tahiti.
We can use one day to refer to the future.
One day, you will regret this.

We use one or one of… when we mean one person/thing out of many. It usually contrasts with another/other(s).
One bus was full, but the others were empty.
One of my colleagues is from Italy.
One / Ones
 We use one in the singular and ones in the plural to avoid repeating the noun when it is clear what we mean.
My house is the one with the red front door.
 We use a / an with one when there is an adjective before it.
I want to buy a jacket. I want a leather one. VS. I want to buy a jacket. I want one with a fur collar.
 We use one / ones with this/ that.
I don’t like this pair of shoes, but I like that one.
 We use which one(s) in questions.
I like the yellow blouse best. Which one do you like?