Potvrdu o prijavi čuvajte dok traje privremeni odlazak.

Because it is the direct object of the imperative verb čuvajte (keep).

• potvrda = nominative singular (a certificate / confirmation)
• potvrdu = accusative singular

In Croatian, a direct object often goes into the accusative case, so:

• Čuvajte potvrdu = Keep the certificate

That is why you see potvrdu here.

Because the preposition o normally takes the locative case when it means about / concerning.

So:

• prijava = nominative
• prijavi = locative singular

In this phrase, potvrda o prijavi means something like confirmation/certificate of registration or confirmation regarding the registration.

This is a very common administrative pattern in Croatian:

• odluka o nečemu = decision about something
• obavijest o nečemu = notice about something
• potvrda o nečemu = confirmation/certificate of something

So o prijavi is there because of the noun phrase, not because of the verb čuvajte.

Čuvajte is the imperative form of čuvati (to keep, guard, preserve, retain).

More specifically, it is the 2nd person plural imperative:

• čuvaj! = keep! (singular, informal)
• čuvajte! = keep! (plural, or formal singular)

So in this sentence, it could mean:

• speaking to more than one person, or
• speaking formally to one person

In official notices and administrative language, čuvajte is very common because it sounds polite and standard.

It can be both.

Croatian uses the 2nd person plural form to address:

1. more than one person
2. one person formally (like Vi)

So this sentence could be aimed at:

• several people: Keep the certificate...
• one person in a formal context: Please keep the certificate...

In government, legal, or administrative instructions, this formal/plural form is extremely common.

Because Croatian often omits subject pronouns when the verb ending already shows the person.

Here, čuvajte already tells you the subject is you (plural/formal), so vi is unnecessary.

Likewise, traje tells you the subject is he/she/it, and in this sentence that subject is privremeni odlazak.

So Croatian often sounds more compact than English because the verb form carries more information.

Here dok means while or for as long as.

So the structure is:

• čuvajte ... dok traje ...
• keep ... while / as long as ... lasts

Depending on context, dok can also mean until, but in this sentence the most natural sense is for the duration that the temporary departure lasts.

So the idea is not just a simple time point; it means during the whole period.

Traje is the 3rd person singular present tense of trajati (to last).

It agrees with the subject privremeni odlazak, which is singular:

• odlazak traje = the departure/absence lasts

So:

• dok traje privremeni odlazak = while the temporary departure lasts

The verb is singular because odlazak is singular.

It is in the nominative singular because it is the subject of the verb traje.

In the clause:

• privremeni odlazak traje = the temporary departure lasts

the thing doing the lasting is privremeni odlazak, so it appears in the nominative.

Forms here are:

• odlazak = masculine singular nominative
• privremeni = adjective matching odlazak in gender, number, and case

Because privremeni is the form that agrees with the masculine noun odlazak in the nominative singular in this usage.

Croatian adjectives change form to match the noun they describe. Here:

• odlazak = masculine singular nominative
• therefore the adjective also matches: privremeni odlazak

For learners, it is useful to remember this as the standard dictionary-style phrase:

• privremeni odlazak = temporary departure / temporary absence

Croatian word order is fairly flexible, and the object can be placed first for emphasis or because it sounds natural in formal instructions.

So:

• Potvrdu o prijavi čuvajte...
• Čuvajte potvrdu o prijavi...

Both are grammatical.

Starting with Potvrdu o prijavi puts immediate focus on the document you must keep. That is very typical in official or bureaucratic language.

It sounds formal / administrative.

Clues include:

• the noun phrase potvrda o prijavi
• the instruction-style imperative čuvajte
• the official expression privremeni odlazak

In everyday speech, people might say something simpler depending on context, but in forms, notices, and legal/administrative communication, this wording is very natural.

No. Croatian does not have articles like a or the.

So potvrdu by itself can mean:

• a certificate
• the certificate

The exact meaning depends on context. In this sentence, because it is an official instruction about a specific document, English would usually translate it as the certificate or the confirmation.

Yes, or at least a very natural set administrative phrase.

It literally breaks down as:

• potvrda = confirmation/certificate
• o prijavi = about the registration/application/report

But together it functions as a standard official document name: certificate/confirmation of registration.

This is important for learners because the phrase may not translate word-for-word as naturally into English as it sounds in Croatian. In bureaucratic Croatian, this type of noun + o + locative structure is very common.

Not most naturally in this sentence.

Dok can sometimes overlap with until, but here the sense is more clearly:

• while
• for as long as

That is because the instruction is about keeping the document during the whole period of the temporary departure.

If you translated it as until, English might suggest only the endpoint, while Croatian here strongly suggests the full duration.

It has two parts:

1. Potvrdu o prijavi čuvajte

   • main clause
   • imperative
   • Keep the certificate of registration

2. dok traje privremeni odlazak

   • time clause introduced by dok
   • literally while the temporary departure lasts

So the full structure is:

• [Object] + [Imperative verb] + [time clause]

That structure is very normal in Croatian, especially in instructions and official notices.