Greetings, fellow English board users.

Knowing how to use articles is hard, especially for those (including myself) whose first language is not English (or one of the other languages that have definitive/indefinitive article). Since we don't know if somethin is wrong because it sounds weird (which is the case for those whose first language is English. Think of it this way. We don't think about the rule when it comes to when to use 'eul/reul' or 'eun/neun,' but we just know it naturally because they sound weird when used in the wrong place), we'll just have to learn the rule and practice until we can use it without thinking twice. I found a website that had very good articles regarding the subject, hence wanted to share with everyone. I hope this helps.

http://www.edufind.com/english/grammar/subidx.cfm

DEFINITE ARTICLE

THE

Articles in English are invariable. That is, they do not change according to the gender or number of the noun they refer to, e.g. the boy, the woman, the children

'The' is used:

1. to refer to something which has already been mentioned.

Example: An elephant and a mouse fell in love.
The mouse loved the elephant's long trunk,
and the elephant loved the mouse's tiny nose.

2. when both the speaker and listener know what is being talked about, even if it has not been mentioned before.

Example: 'Where's the bathroom?'
'It's on the first floor.'

3. in sentences or clauses where we define or identify a particular person or object:

Examples: The man who wrote this book is famous.
'Which car did you scratch?' 'The red one.
My house is the one with a blue door.'

4. to refer to objects we regard as unique:

Examples: the sun, the moon, the world

5. before superlatives and ordinal numbers:

Examples: the highest building, the first page, the last chapter.

6. with adjectives, to refer to a whole group of people:

Examples: the Japanese, the old

7. with names of geographical areas and oceans:

Examples: the Caribbean, the Sahara, the Atlantic

8. with decades, or groups of years:

Example: she grew up in the seventies


INDEFINITE ARTICLE

A / AN

Use 'a' with nouns starting with a consonant (letters that are not vowels),
'an' with nouns starting with a vowel (a,e,i,o,u)

Examples:

A boy
An apple
A car
An orange
A house
An opera

NOTE:
An before an h mute - an hour, an honour.
A before u and eu when they sound like 'you': a european, a university, a unit

The indefinite article is used:

• to refer to something for the first time:
  An elephant and a mouse fell in love.
  Would you like a drink?
  I've finally got a good job.
  
• to refer to a particular member of a group or class

Examples:

• with names of jobs:
  John is a doctor.
  Mary is training to be an engineer.
  He wants to be a dancer.


• with nationalities and religions:
  John is an Englishman.
  Kate is a Catholic.


• with musical instruments:
  Sherlock Holmes was playing a violin when the visitor arrived.
  (BUT to describe the activity we say "He plays the violin.")


• with names of days:
  I was born on a Thursday

• to refer to a kind of, or example of something:
  the mouse had a tiny nose
  the elephant had a long trunk
  it was a very strange car


• with singular nouns, after the words 'what' and 'such':
  What a shame!
  She's such a beautiful girl.


• meaning 'one', referring to a single object or person:
  I'd like an orange and two lemons please.
  The burglar took a diamond necklace and a valuable painting.

Notice also that we usually say a hundred, a thousand, a million.

NOTE: that we use 'one' to add emphasis or to contrast with other numbers:
I don't know one person who likes eating elephant meat.
We've got six computers but only one printer

EXCEPTIONS TO USING THE DEFINITE ARTICLE

There is no article:

• with names of countries (if singular)
  Germany is an important economic power.
  He's just returned from Zimbabwe.
  (But: I'm visiting the United States next week.)



• with the names of languages
  French is spoken in Tahiti.
  English uses many words of Latin origin.
  Indonesian is a relatively new language.



• with the names of meals.
  Lunch is at midday.
  Dinner is in the evening.
  Breakfast is the first meal of the day.



• with people's names (if singular):
  John's coming to the party.
  George King is my uncle.
  (But: we're having lunch with the Morgans tomorrow.)



• with titles and names:
  Prince Charles is Queen Elizabeth's son.
  President Kennedy was assassinated in Dallas.
  Dr. Watson was Sherlock Holmes' friend.
  (But: the Queen of England, the Pope.)



• After the 's possessive case:
  His brother's car.
  Peter's house.



• with professions:
  Engineering is a useful career.
  He'll probably go into medicine.



• with names of shops:
  I'll get the card at Smith's.
  Can you go to Boots for me?



• with years:
  1948 was a wonderful year.
  Do you remember 1995?



• With uncountable nouns:
  Rice is the main food in Asia.
  Milk is often added to tea in England.
  War is destructive.



• with the names of individual mountains, lakes and islands:
  Mount McKinley is the highest mountain in Alaska.
  She lives near Lake Windermere.
  Have you visited Long Island?



• with most names of towns, streets, stations and airports:
  Victoria Station is in the centre of London.
  Can you direct me to Bond Street?
  She lives in Florence.
  They're flying from Heathrow.



• in some fixed expressions, for example:
  by car
  by train
  by air
  on foot
  on holiday
  on air (in broadcasting)
  at school
  at work
  at University
  in church
  in prison
  in bed