Here are some of the most important things to know about using articles.
Jobs
When we say what people's jobs are, we usually use a/an.
He's an architect.
She's a scientist.
My grandmother was a teacher.
Singular nouns
Singular, countable nouns always have an article – a/an or the (or another determiner – my, your, this, that, etc.).We use a/an – the indefinite article – when we talk about something for the first time, or something that is part of a group or type.
I saw a good film yesterday.
Do you want a drink?
We use a when the word that follows it begins with a consonant sound. We use an when it's followed by a vowel sound. This makes pronunciation easier.
She has a university degree.
It took me an hour to get home.
We use the – the definite article – when the listener already knows which thing we are talking about because it was mentioned before or because there's only one of them.
I'm going to take the dog for a walk.
Have you seen the car key?
They go to the school next to the bridge.
Things in general
When we talk about things in general, we normally use a plural or uncountable noun with no article.
Birds eat worms.
Water freezes at 0°C.
Children need a lot of sleep.
Particular groups of things
When we talk about a particular group of things, we use the.
We went to the zoo and saw the kangaroos. (These are the particular kangaroos in that zoo – not kangaroos in general.)