THE INDEFINITE ARTICLE – A, AN Is used: Before a singular countable noun a dog, a man, an apple
A / an has no plural form. In plural, instead of a, we use either no word at all, or some: This is a cat. These are cats. That is a tree. Those are trees. There is a dog. There are some dogs.
The indefinite article It is used after to be / to become and before a noun which indicates a profession: He is a student. She wants to become an actress.
The indefinite article has the meaning of ONE and is used in front of “large numbers” A thousand, a hundred, a dozen, a million
The indefinite article A / an is used when something is mentioned for the first time, but when the same thing is mentioned again, use the I saw a man. The man was wearing a coat. The coat was black.
The indefinite article A / an is used the same as one when it contrasts with two, three… I’d like two cups of tea and a glass of milk. A / an also means “per” or “every” in phrases of measuring of frequency: Once / twice / six times / …times – a day / a week / a month / a year
The indefinite article A / an is used in phrases denoting speed, size, quantity, etc. Sixty miles an hour. Two pounds a kilo.
The indefinite article A / an also has a general use, which describes all examples of the same kind, or any examples of the same kind. What is a dictionary? A dictionary is a book which tells you about the meanings of words. If a man and a woman are in love, they will have a happy marriage.
The indefinite article A / an is used in phrases: a bit of, a few, a little, a great deal of, a good many, a large number of, a lot of..
The indefinite article A / an is used after such, what, quite, rather What a nice young man! She was such a kind person. We had quite/rather a busy day. A piece of cake, a type of car,… many a man died in that battle.
The indefinite article A / an in proverbs and sayings An apple a day keeps the doctor away. In front of a family name meaning “a certain, I don’t know who” – A Mr. Brown wants to see you, sir.