Countable nouns

Countable nouns are nouns that we can count: car, house, book, etc.

We can say one car, two cars, three cars, etc.

Countable nouns have singular and plural forms: a car/cars, a house/houses, a book/books, etc.

A/an + singular countable noun

We CANNOT use a singular countable noun without a determiner like a/an, the, my, your, her, etc.

I have car. 

I have a car. 

When I was child. 

When I was a child.