Definite Article - the
determiners
There are two ways to pronounce "the": "thuh" and "thee". To learn how to pronounce them see the pronunciation files: How to pronounce "the".
You use the when you have already mentioned the thing you are talking about.
| For example: | "She's got two children; a girl and a boy. The girl's eight and the boy's fourteen." | 
We use the to talk about geographical points on the globe.
| For example: | the North Pole, the equator | 
We use the to talk about rivers, oceans and seas
| For example: | the Nile, the Pacific, the English channel | 
We also use the before certain nouns when we know there is only one of a particular thing.
| For example: | the rain, the sun, the wind, the world, the earth, the White House etc.. | 
However if you want to describe a particular instance of these you should use a/an.
| For example: | "I could hear the wind." / "There's a cold wind blowing." "What are your plans for the future?" / "She has a promising future ahead of her." | 
The is 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 whether or not it preceeds a vowel:
| For example: | "Harry's Bar is the place to go." "You don't mean you met the Tony Blair, do you?" | 
!Note - The doesn't mean all:-
| For example: | "The books are expensive." = (Not all books are expensive, just the ones I'm talking about.) "Books are expensive." = (All books are expensive.) | 
