1. Przedimek nieokreślony- The indefinite article a / an!

If some noun starts with a letter sounding like vowel, we put the indefinite article 'an' in front of it. When it starts with a letter sounding like consonant, we out 'a' in front of it.

An egg, an onion, an intelligent woman, an aunt

a ball, a union, a letter

We use the indefinite article mostly, when:

a. mentioning something countable the first time in the speech;

I saw a book lying on a bank…

I heard a song.

b. we are going to say, what something is like, or to group things;

She is a very brilliant person.

I am a good student.

c. we give a name to someone's job;

John is a teacher.

  1. In front of some numbers and in expressions with numbers;

A hundred, a thousand, a million…

I earn a thousand and ten dollars a week.

We walked two kilometers an hour.

They practise 6 days a week.

2. Przedimek określony- The Definite Article 'the'.

We use this article mostly, when:

a. we mention something, that has already been mentioned;

To prepare a delicious tomato soup, you need one kg of tomatoes, an onion and oil. The soup is best, when you first slice the onion … 

b. we tell someone about a thing that he/she knows or about something, that we have already defined; I am going to read the book, you told me about.

c. there exists only one thing/person of some kind (in given context );

The Earth goes around the Sun.

Could you tell the coach to call me? 

The market square in this city is very picturesque.

d. when the adjective is in the superlative;

He is the best swimmer in Poland.

You are the noisiest person I know.

e. considering musical instruments;

She plays the trumpet and I play the saxophone.

f. telling about means of transportation;

He would rather drive the car than go take the plane.

g. regarding inventions.

The bulb was invented many years ago.

h. telling about the species of animals in the singular form;

The tiger lives in Asia and it is the predator.

i. using an adjective as a noun- when we classify a group of things or people.