Determiners are words such as this, those, my, their, which. They are special adjectives that are used before
The words a, an and the belong to this group of words called determiners.
The words a and an are called indefinite articles. You can use them with singular nouns to talk about any
single person or thing.
This is a picture of an elephant.
Rudy is reading a book.
Mom bought me a new dress today.
You will need an umbrella when you go out.
She eats an apple a day.
The word the is called the definite article. Use the before a noun when you are talking about a certain person or thing.
Granny is sitting in the garden.
The street is very busy today.
The sky is getting dark.
Kaynak: Basic English Grammer Book1