Sometimes we don't use any article at all.
We need zero article, or no article, when we should put an indefinite article but it is not possible:
- if the noun is uncountable (water, jam, fun etc.)
- if a countable noun is plural
I've got bread, butter and jam.
It’s fun to learn languages.
There are books and magazines on the shelf.
Children and adults can play this game.
Remember other cases when we use zero article
to have dinner
to have something for breakfast
to go out for lunch
- expressions with the words work, home, university, college, school, bed
to go to work, to be at work
to go home, to be at home
to go to university/college/school
to be in bed, to go to bed
- means of transport, to go by something
to go by bus, by train, by plane, by car, on foot
- this / next / last + week / month / year etc.
What are you doing this weekend?
I’ll be out of office next Monday.
I went to Cuba last year.
Joann was very busy last month.