The three aticles in English are a, an and the. They are used before nouns to give us more information.
A and an are indefinite articles. Use indefinite articles before countable nouns.
Use a/an when it is not imortant or not known which thing (noun) we are talking about.
Let's watch a movie tonight. - Which restaurant hasn't been decided yet.
Use a/an when the noun is part of a group
She's a member of the golf club.
Use a when the next word is a consonant and when the following noun starts with a u or eu which sounds like 'yoo'.
We took a taxi. - taxi starts with a consonant.
She drew a unicorn. - the u in unicorn is pronounced yoo.
A European flag. - the e in European is pronounced yoo.
Use an when the next word starts with a vowel (a,e,i,o,u) or with a silent h.
The is called a definite article. We use the when we are talking about specific nouns i.e. when we know exactly which one we are talking about.
Also use the when it is assumed there is only one of that thing in a place.
I broke the umbrella I bought yesterday. - we are talking about a specific umbrella.
The flowers you gave her are beautiful. - we are talking about of specific flowers.
Shall we go to the cinema? - we assume there is only one in that area.
Excuse me, where is the bathroom? - we assume that place only has one bathroom.
Now decide if these sentences need a, an or the: