articles

A/AN
•Use a/an to mention something for the first time (e.g. There's a swimming pool near here)
•Use a/ an to describe a person's job or character (e.g. She was an engineer, he's a )
•Use a/ an to generalize a singular noun (e.g. It's important to get a good night's sleep)
•Use a/ an when we refer to an individual example of a product made by a particular manufacturer (e.g. He's bought an iPhone)
•Use a/ an when we are saying what type of noun something is (e.g. a great movie, a big breakfast)
THE
•Use the when there is only one of something or one set of them
(e.g. the equator, the Internet, Paris is the capital of France)
•use the before same, maximum and main (e.g. the same dress)
• Use the when a noun, or a characteristic or property of a noun has already been mentioned (e.g. The gym is great but the changing rooms are horrible)
•Use the with superlatives and ordinal numbers (e.g. the best, the first)
•use the to make generalizations about classes of things using singular countable nouns (e.g. The computer has revolutionized publishing - referring to computers in general)
When not to use 'THE'
• With the names of meals, e.g. What did you have for the breakfast?
• With a noun and number, e.g. Our train leaves from the Platform 5.
•When talking about things or people in general, e.g. The men are different from the women.
•To make a generalization about uncountable and plural nouns
e.g. I like dogs.
Note that some nouns are uncountable when we talk about the whole substance or idea, but countable when we talk about an instance or more than one instead of it.
e.g.
I love coffee. Would you like a cup of coffee?
He's got dark hair. There's a hair in my soup!
Red meat is high in iron. Each room has an iron and ironing board.
The Andes <- range/ many mountains all together
Mount kilimanjaro <- a single mountain
The moon
a full moon
a crescent moon