There was a really good answer from a native Romanian on a previous phrase that was similar to this and I copied it to Word so I could read it later because it's really long!
Here it is:
Simply put: different languages have different rules for when to use articles.
Short version, that works in a lot of situations:
When using the definite article in English, you would use no article in Romanian:
We are going to the circus. - Mergem la circ.
When using the indefinite article in English, you would the indefinite article in Romanian:
We are going to a circus. - Mergem la un circ.
(the nuances in English are kept in Romanian).
These rules are kinda complicated, I'll try my best:
The definite article is omitted with nouns preceded by a preposition that is not "cu" (with)
The child is at the table. - Copilul e la masă.
The food is on the table. - Mâncarea e pe masă.
The chair is next to the table. - Scaunul e lângă masă.
But is required when using an adjective with said noun
The child is at the large table. - Copilul e la masa mare.
The food is on the white table. - Mâncarea este pe masa alba.
The chair is next to the tall table. - Scaunul e lângă masa** înaltă.
And is required with "cu"
He is leaving with the chair. - El pleacă cu scaunul.
We are going by car. - Noi mergem cu mașina.
However, it is ommited with cu if talking about adding something (having a property)
Lemon tea. - Ceai cu lămâie.
House with wheels. - Casă cu roți.
The definite article is also required when talking about family members
I talked to mom about this. - Am vorbit cu mama (not mamă) despre asta.
He is your uncle. - El este unchiul tău.
Or when adding a possesive adjective
He is your friend. - El este prietenul tău.
She stole your pencil. - Ea ți-a furat creionul.
The indefinite article is not required when talking about the status of someone (religion, nationality, sex etc.)
He is a man. - El e bărbat.
She is a student. - Ea este studentă.
Bob is a muslim. - Bob e musulman.
However, it is required when adding an adjective to said status
He is a kind man. - El e un om bun.
She is a lazy student. - Ea este o studentă leneșă.
Bob is a devout muslim. - Bob e un musulman devotat.
The indefinite article is not required when talking about two objects in some relation (I don't know how to express this)
It's a chair, not a table. - E masă, nu scaun.
Is it a spoon or a fork? - E lingură sau furculiță?
The indefinite article is ommited with nouns preceded by interrogative/indefinite pronominal adjectives
What a great book! - Ce carte grozavă!
In all other cases, things should be the same in both languages, unless I am forgetting something.
"required" means that the article must be there.
"not required" means that the article may or may not be there.
"ommited" means that the article must not be there.
Disclaimer: I am a native speaker, but I might have forgotten some obscure exceptions to these rules.