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1     a/an (the indefinite article)

The form a is used before a word beginning with a consonant, or a vowel with a consonant sound:

a man      a hat      a university      a European

a one-way street

The form an is used before words beginning with a vowel (a, e, i, o, u) or words beginning with a mute h:

an apple        an island         an uncle

an egg           an onion          an hour

or individual letters spoken with a vowel sound:

an L-plate      an MP      an SOS      an 'x' a/an is the same for all genders:

a man      a woman      an actor      an actress      a table

2     Use of a/an. 

a/an is used:

    A.     Before a singular noun which is countable (i.e. of which there is more than one) when it is mentioned for the first time and represents no particular person or thing:

/ need a visa.       They live in a flat.       He bought an ice-cream.

    B.     Before a singular countable noun which is used as an example of a class of things:

A car must be insured All cars/Any car must be insured.

A child needs love = All children need/Any child needs love.

   C.     With a noun complement. This includes names of professions:

It was an earthquake.       She'll be a dancer.       He is an actor.

   D.     In certain expressions of quantity: a lot of                   a couple

a great many           a dozen (but one dozen is also possible)

a great deal of

   E.     With certain numbers

a hundred      a thousand      (See 349 ) Before half when half follows a whole number

ll/2 kilos = one and a half kilos or a kilo and a half But 1/2 kg = half a kilo (no a before half), though a + half + noun is sometimes possible

a half holiday       a half portion       a half share With 1/3 1/4, 1/5 etc a is usual a third, a quarter etc , but one is also possible (See 350 )

 F.     In expressions of price, speed, ratio etc

5p a kilo            £1 a metre                sixty kilometres an hour

lOp a dozen       four times a day (Here a/an = per )

 G.     In exclamations before singular, countable nouns

Such a long queue'       What a pretty girl'      But Such long queues'       What pretty girls' (Plural nouns, so no article  See 3 )

 H.     a can be placed before Mr/Mrs/Miss + surname

a Mr Smith      a Mrs Smith      a Miss Smith

a Mr Smith means 'a man called Smith' and implies that he is a stranger to the speaker Mr Smith, without a, implies that the speaker knows Mr Smith or knows of his existence

(For the difference between a/an and one, see 4  For a few and a little, see 5 )

3    Omission of a/an

a/an is omitted:

A.     Before plural nouns

a/an has no plural form. So the plural of a dog is dogs, and of

an egg is eggs

B.     Before uncountable nouns

C.     Before names of meals, except when these are preceded by an adjective

We have breakfast at eight

He gave us a good breakfast

The article is also used when it is a special meal given to celebrate something or in someone's honour

I was invited to dinner (at their house, in the ordinary way) but

I was invited to a dinner given to welcome the new ambassador