Specific Uses of English Grammar Articles

In this case Example Sentence

Use "a" / "an" You mention something
for the first time. I have a problem.
You want to say that something belongs to a certain group. This is a table.
You want to say that someone belongs to a certain group. She is a designer.
You want to say that
something is that kind of thing. I've built a strong ship.
You want to say that
someone is that kind of person. He is a nice guy.
Use "the" You talk about a specific thing. The feeling I got was very strange.
It is clear which thing
you are talking about. I passed the test!
There is only one such thing. Look at the sun.
No article You talk about
something in general. Pigs can't fly.
Diving can be difficult.
You talk about cities,
countries, streets, etc. We visited Italy.