Questions & Answers about Vidim nešto u uredu.
What case is nešto in this sentence, and why didn't its ending change?
Nešto (something) is in the accusative case here because it is the direct object of the verb vidjeti (to see). For the pronoun nešto, the accusative form is exactly the same as the dictionary form, so it doesn't change.
Could I use netko instead of nešto here to say I see 'someone'?
Yes, but the word would change. Because the verb takes the accusative case, netko (someone) must change to its accusative form, nekoga. You would say: Vidim nekoga u uredu.
If I want to say 'I see nothing' in the office, do I just swap nešto for ništa?
Not quite! Croatian requires a double negative. You must use ništa (nothing) and also make the verb negative. The correct sentence would be: Ne vidim ništa u uredu.
Why does ured (office) become uredu?
It is in the locative case. The preposition u (in) takes the locative case when describing a static location (where something is right now). Since the thing you see is located inside the office, we add the locative -u ending to the masculine noun ured.