The vs A/An

Related to my previous post is the difference between the articles the and a or an when they come before a noun. I mentioned earlier that the is used to specify which item/person/place the noun means. However, it's just as correct to say a house as it is to say the house. What's the difference between the two?

It's very simple really. English grammar rules say that the is used when you're referring to something specific. So, "I saw the book you want at the bookstore at the ground floor." In all cases, the speaker is talking about a specific book, store, and floor. Notice the difference here: "I saw a book you might want to buy. I think it's available in a store located next to the grocery."

Depending on what you're trying to say, the, a, and an can change the meaning of your words. Be sure to use them correctly and don't forget them.