Questions & Answers about Mobilna mreža radi dobro.
- mobilna = mobile
- mreža = network
- radi = works / is working / functions
- dobro = well
So the sentence literally looks like Mobile network works well, and in natural English that is The mobile network works well.
Because mobilna has to agree with mreža.
Mreža is:
- feminine
- singular
- here in the nominative case, because it is the subject of the sentence
So the adjective must also be feminine singular nominative:
- masculine: mobilni
- feminine: mobilna
- neuter: mobilno
That is why you get mobilna mreža.
Yes, mreža is feminine.
A very common clue in Serbian is that many feminine nouns in the dictionary form end in -a, and mreža does. That pattern is not perfect for every noun in the language, but it is very common and useful.