Indefinite Articles : a,an (2º)

Articles: Indefinite articles: a, an.
The words a and an are called articles.

We use 'a' before the naming word starting with consonants.
Example: A girl, a dog, a bag.

We use 'an' before the naming word starting with vowels.
Example: An apple, an owl, an igloo.

We use 'a' or 'an' when we talk about one person, animal or thing. 'A' or 'an' show only one thing.
We say 'a dog' when we talk about one dog.
We say 'an apple' when we talk about one apple.