Questions & Answers about Gde su moje čarape? Vidim ih na krevetu.
Gde means where in the sense of location.
So:
- Gde su moje čarape? = Where are my socks?
Serbian often distinguishes different kinds of where:
- gde = where, at what place
- kuda = where to / which way
- odakle = from where
So here gde is correct because the question is about the socks’ location.
Su is the normal short form of to be for they are.
- su = short, unstressed form
- jesu = full form, usually used for emphasis or contrast
In a neutral question, Serbian normally uses su:
- Gde su moje čarape?
You would use jesu only if you want emphasis, for example:
- One jesu na krevetu, nisu u fioci. = They are on the bed, not in the drawer.
Also, su is a clitic, so it typically comes early in the sentence, often after the first word or phrase. That is why Gde su... sounds natural.