Determiner modifier head qualifier

2.1. The use of the indefinite articles a/an

The indefinite article a/an is the normal, neutral and most typical way of referring to a single example of something, to one member of a class of things. It is also used to refer to a thing for the first time.

A/An is used:

1. To refer to a group of people, animals or things:We could call it a sort of romance between just a man and a woman. A dolphin lives in the sea.

NOTE: In this case the article has the meaning any or every.

1) in classification by means of descriptive labels:

a) origins: He is a Frenchman.

b) occupation:I'm anarchitect.

c) religion:She's aCatholic.

d) politics: He isaSocialist.

NOTE: Adjectival equivalents (where they exist) can be used in place of nouns for all the above examples except occupation: He's American / Catholic /Socialist.

2) with any kind of typical characterization: You are an angel/ a saint /a beauty/ a chatter-box/ a lunatic.

3) with nouns in apposition to state that the object expressed by the noun in apposition belongs to a certain class: I'd like to introduce you to Mr Smith, a great friend of mine.

4) with pairs of nouns which are considered to accompany each other naturally: a cup and saucer; a hat and coat. It's cold outside, takea hat and coat with you.

NOTE:Take a hat anda camera when you go on holiday (here a hat and a camera do not form a pair.)

2.With nouns in certain syntactical positions:

1) with nouns modified by:

a) a descriptive attribute: I spent asleepless night. It was a cold spring. We left the place after ahearty breakfast.

b) a descriptive infinitive: I made an attempt to smile.

2) with a noun followed by a qualifier, such as a prepositional phrase or a relative clause: The information was contained in anarticle on biology. I chose apicture that reminded me of my own country.

3. 1) To preserve its old original meaning of one: A stitch in time saves nine. In some languages, one and a/an are the same. In English a/an is more common. One is only used:

a) when we want to be particularly emphatic or dramatic, meaning "no more than one":. He's got one son. (not two or three);

b) when we are explicitly contrasting numbers, e.g. two kilos of flour and one litre of water; She's got one Rolls-Royce and two Cadillacs or in technical mathematical contexts;

c) when we want to highlight something or someone in a report or story, and make them an important topic we are going to talk about. The expressions like One day ... and One morning... are familiar openings to important events in stories.

2) with uncountable nouns to mean one: There is ahair in my soup.

4. With abstract nouns:

1) with abstract nouns used in a particular sense: a love of music, alove of nature.

2) with some abstract nouns like regret, comfort, pity, horror, shame, relief, wonder, etc.: It's a pity/relief/ shame/ wonder/ horror, etc

3) with abstract nouns to denote a certain kind of a quality, feeling, state, etc., which are modified by a descriptive attribute or an attributive clause: We saw an eagerness in her eyes, which could hardly be forgotten.

5. With numerals:

1) with numerals hundred, thousand, million to mean one and the nouns that refer to whole numbers, fractions, money, weights or measures, time: A week has passed. The case weighs ahundred pounds. We go there twice afortnight.

NOTE: In measuring per can replace a/an: He was paid $30 a/per day.

2) with ordinal numerals meaning one more or another: He must have athird attempt.

3) with the nouns period, population, distance, height, salary, etc followed by of + numeral + noun: She was working for aperiod of ten days. So far we have covered a distance of thirty miles.

4) with some expressions of quantity: a pair of, a little, a couple of, a few; three times a day; forty miles an hour; He bought apair of shoes.

6. In exclamations with What + a countable noun: What anidea! What alovely day! What a beautiful sight!

7. After half, many, quite, such, rather: There was half acup of coffee left. He spent many alonely day there. She is quite a child.

NOTE: A or an either precedes or follows rather: Seaford is rather a pleasant town. He told me arather long story.

8. To follow the attribute expressed by an adjective after as, how, so, too: It was as black a house inside as outside. She is too agood woman for him.

9. With uncountable nouns to express the meaning 'a type of' or 'a portion of': a gin, an ice-cream, asoup.

10. With some illnesses: a cold, aheadache, asore throat, aweak heart, abroken leg.

NOTE: Ais optional in the expressions like catch (a) cold, have (a)backache/ stomach-ache/ toothache/ earache, e.g.: I'm afraid the baby's got (a) cold. I've had (a)toothache all night.