The indefinite article – We use ‘a’ or ‘an’ if we want to talk about a single thing that is part of a group. We also use it when talking about something for the first time.
I went to a new restaurant last week.
Do you want an apple?
If the word that follows the article begins with a vowel (a,e,i,o,u) we use the ‘an’ article. If the word uses a consonant (not a vowel) then we use the article ‘a’.
She has an elephant.
I will eat a pie today
The definite article –’The’ is used when there is only 1 of something, or we already know the subject of the conversation, as it has been said before, or implied.
Did you feed the cat?
I am taking the bus to school.
Can you pass me the salt, it’s next to the cup