Вы уже знаете основные правила употребления артиклей.

 
THE
 
Определённый артикль the употребляется с существительными, когда после них стоят пояснительные слова, например:

• It is the title of the chapter. - Это - название иного раздела.
• Не was haunted by the fear that no one would turn up. - Его мучая страх, что никто не придёт.

Неопределенный артикль употребляется перед нарицательными исчисляемыми существительными в единственном числе (an hour, an MP, an SOS, a university, a European law, a one-way street).
1.    в значении «один из», «какой-то», «любой»: There is a letter on the table. Shall we choose a booh from this catalogue?
2.    в значении «один», «ещё один»: Wait a minute, please. He took a second opportunity to overcome the difficulties.

Неопределенный артикль употребляется перед нарицательными исчисляемыми существительными в единственном числе (an hour, an MP, an SOS, a university, a European law, a one-way street).

• в значении «один из», «какой-то», «любой»: There is a letter on the table. Shall we choose a booh from this catalogue?
• в значении «один», «ещё один»: Wait a minute, please. He took a second opportunity to overcome the difficulties.
• с числительными: a million dollars; 1/3 = a third; 5p a (per) kilo, 4 times a (per) day, 1.5 hours = one and a half hours, cm hour and a half; 0.5 hour = half an hour.
• если предмет упоминается впервые: I sent you an e-mail yesterday.

В английском языке существует одна форма определенного артикля  (the) и две формы неопределенного артикля: а перед согласными и буквой и an перед гласными.

• The man is eating an apple and a banana.
  Мужчина ест яблоко и банан.
  

Определенный артикль не требуется в следующих случаях:

С названиями дней недели и времен года:

• next Tuesday
  в следующий вторник
  

С существительными, обозначающими отвлеченные понятия:

• Love is blind.
  Любовь слепа.
  

Common expressions without articles

Articles are not used in these expressions:

to school     at school     from school     to/at/from university/college to/at/in/into/from church     to/in/into/out of bed/prison/hospital to/at/from work     to/at sea     to/in/from town     at/from home for/at/to breakfast/lunch/dinner/supper     at night by car/bus/bicycle/plane/train/tube/ boat on foot     go to sleep     watch television (TV)     on TV

Possessives

A noun that is used after a possessive (like John's, America's), has no article.

• John's coat (NOT the John's coat)
• America's economic problems (NOT the America's economic problems)

Grammarians are not always agreed as to the grammatical status of the article in Modern English.
In structural grammars the article is often dispensed with as a separate part of speech and absorbed into the adjective class.

The name "determiners" is then given to closed system items, which, functioning as adjuncts, show their head-words to be nouns. The most central type of "determiner" is that to which we traditionally give the name article.

Article introduces a noun and indicates how specific the noun is.
English has two articles: the definite article "the" and the indefinite article "a" (or "an").

INDEFINITE ARTICLE (A, AN)

Use a (or an) only before singular count nouns.

A (or an) means, approximately, "one." "I saw a cat" and "i saw one cat" describe the same event, but "I saw one cat" emphasizes that there was only one cat, not two.

Use the indefinite article to introduce...

1. Nonspecific, unknown nouns:

• He entered a brown building. 
• There is an apple on the tree.

2. One of a general group:

• A computer can do many things.

Ни для кого не секрет, что обучение употреблению английских артиклей представляет определенные трудности как в школьной, так и в вузовской аудитории. Думается, что предлагаемый в данной статье подход позволит перейти от изучения отдельных случаев употребления артиклей к общему принципу, регулирующему выбор артиклей в зависимости от определенной коммуникативной ситуации (прагматических условий).

A / an are determiners. Determiners are words we use before a noun to show whether the noun is specific or general, singular or plural, etc.

A/an

We use a or an with singular countable nouns only. A and an are indefinite articles. We use them to talk about one of something when we assume that the listener / reader doesn't know which specific thing:

• A car drove past. (= we don't know exactly which car)

The

We use the with countable nouns (singular or plural) and uncountable nouns:

• A man is coming round to fix the television.
• Let's sit on the grass over there.

The is the definite article. We use it to talk about a specific example of something we think is known to both ourselves and the listener / reader:

• The cars were parked illegally in the city centre. (= we know which cars and which city)

When do we say "the dog" and when do we say "a dog"? (On this page we talk only about singular, countable nouns.)

The and a/an are called "articles". We divide them into "definite" and "indefinite" like this:

We use "definite" to mean sure, certain. "Definite" is particular.

We use "indefinite" to mean not sure, not certain. "Indefinite" is general.