The indefinite article
There are two indefinite articles in English: a and an. Indefinite articles are invariable. You use one or the other, depending on the first letter of the word following the article. Use a when the next word starts with a consonant, or before words starting in u and eu (if they are pronounced with the consonant sound / j /). Use an when the next word starts with a vowel (a,e,i,o,u) or with a mute h.
An old man
An ugly woman
The indefinite article is used with countable nouns to refer to something for the first time or when the hearer/reader does not know exactly which one we are referring to:
He bought a book yesterday.
There is a telephone in the room.
We also use it to show the person or thing is one of a group; before professions and job titles, nationalities and religions in the singular:
My brother is an engineer.
This is a dictionary.
Ricardo is an Italian footballer.
Mary is a buddhist.
The indefinite article is used to say something about all things of that kind:
A child can understand it (=All children)
A triangle has three sides (=All triangles)
Use a with singular nouns after the words "what" and "such":
What a shame !
She's such a clever girl!
What a lovely day!
Do not use the indefinite article with plural nouns and uncount nouns:
These are such unteresting books. (= plural noun)
Have you ever seen such weather? (= uncount noun)
The indefinite article is used with meaning "one", referring to a single object or person, or a single unit of measure:
I'll come in an hour.
He didn't say a word.
He bought one kilogram of sugar.
You can't run a mile in 5 minutes.
He has won a thousand pounds.
We use the indefinite article in the following phrases and expressions:
A lot of
A great deal of
A great number of
To have a cold/headache
To have a good time
To be in a hurry
For a short (long) time
The definite article
The word "the" is the most common words in English. We use the definite article "the" to refer to something or someone both speakers in a conversation know about or to something or someone which has already been mentioned:
Please close the window.
When I entered the room, I saw a man. The man was very old.
We use the definite article the if there is only one of these people or things (even if it has not been mentioned before) or if you define or identify a particular person or object:
Show me the letter which was received yesterday.
The earth is millions of miles from the sun.
Dad, can I borrow the car?
Look at the girl over there.
The president will be speaking on TV tonight.
Use the before superlatives, ordinal numbers and with decades:
He is the tallest boy in the class.
This is the third time I have visited him.
He was born in the seventies.
This is the best wine I have ever drunk.
We use the definite article the before seas, rivers, and groups of mountains or islands, with countries that have plural names, with countries that include the words "republic", "kingdom", "states", "federation" or "emirates" in their names:
I have never been to the Netherlands.
He is from the Republic of Ireland.
I will go on a cruise down the Pacific Ocean.
They are travelling in the Sahara Desert
Use the with adjectives, to refer to a whole group of people (like rich, poor, elderly, unemployed, family members):
Life can be very hard for the poor.
The Browns have left Paris.
Use the with clauses introduced by same, very, last, following, next, only:
He is the very person I need.
This is the only book I have.
Use the with proper nouns (names of buildings, works of art, museums, monuments, newspapers, hotels & restaurants):
He works for the New York Times.
They would like to visit the Eiffel Tower.
We ate at the Royal Oak.
We use the definite article in the following phrases and expressions:
In the morning/in the evening/in the afternoon/in the night
The day before yesterday/the after tomorrow
To tell the truth
On the other hand
On the right (left)
The Zero Article
We do not use articles (or use the zero article) with names of countries (except for the special cases above), names of languages, people's names, titles:
My father's name is John.
He lives in China.
She was born in Germany
I speak French.
Prince Charles is Queen Elizabeth's son.
We do not use articles with most names of towns, streets, shops, stations, airports, the names of individual mountains, lakes and islands:
They're flying into Gatwick.
New Street Station is in the centre of Birmingham.
Can you go to Asda for me?
The zero article is also used with school, college, hospital, university, and government, class, prison and camp when these are used in their "institutional" sense:
She was taken to hospital.
The zero article is used with plural countable nouns or with mass nouns:
Boys like to play football.
They packed the goods in bags and boxes.
Do not use articles with uncountable nouns, names of meals:
Did you have breakfast this morning?
Milk is often added to tea in England.
The zero article is used with names of sports, games, activities and professions:
I love swimming.
I'll probably study engineering.
The zero article is used with years:
I was born in 1985.
The zero article is used with names of days, months, seasons, holidays and parts of the day:
The zero article is used in the following phrases and expressions:
At first sight
By train, bus,plane etc
By sea, by land, by air