There are only three articles in English: a, an a the.
There are two types of articles: indefinite "a" and "an" or the definite - "the". You also need to know when not to use an article.
A and an are indefinite articles. They are used when talk about something that is not specifically known to the person you are talking to with. A and an are used before nouns that introduce something or someone you have not mentioned before.
A and an are also used when talking about your profession.
You use A when the noun you are referring to begins with a consonant: a house, a building, a car.
You use An when the noun you are referring to begins with a vowel (a, e, i, o, u).
Pronunciation changes this rule. It’s the sound that matters, not the spelling.
If the next word begins with a consonant sound when we say it, for example, "university" then we use a. If the next word begins with a vowel sound when we say it, for example "hour" then we use an.
We say "university" with a "y" sound at the beginning as though it were spelt " you niversity". - So, "a university" IS correct.
We say "hour" with a silent h as though it were spelt "our". - So, "an hour" IS correct.
You use The when you know that the listener knows or can understand what particular person/thing you are talking about.
You should also use The when you have already mentioned the thing you are talking about.
We use The to talk about geographical points on the globe.
We use The to talk about rivers oceans and seas.
We also use The before certain nouns when we know there is only one of a particular thing.
However if you want to describe a particular instance of these you should use a/an.
Theis also used to say that a particular person or thing being mentioned is the best, most famous, etc. In this use, ’the’ is usually given strong pronunciation:
Note - Thedoesn’t mean all.
We usually use no article to talk about things in general..
You do not use an article when talking about sports..
You do not use an article before uncountable nouns when talking about them generally..
You do not use an article before the names of countries except where they indicate multiple areas or contain the words (state(s), kingdom, republic, union). Kingdom, state, republic and union are nouns, so they need an article..