She's a doctor.

I need an umbrella.

Have you heard the news?

I don't like spiders.

Grammar explanation

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.)