Nakon upozorenja o prekidu opskrbe ugasite svijeću i provjetrite sobu.

Nakon means after, and it requires the genitive case in Croatian.

So:

• upozorenje = warning (dictionary form, nominative singular)
• nakon upozorenja = after the warning / after a warning

Here, upozorenja is genitive singular.

A useful rule:

• nakon + genitive

Examples:

• nakon ručka = after lunch
• nakon sastanka = after the meeting
• nakon upozorenja = after the warning

This phrase has two important parts:

• o + locative
• a noun followed by another noun in the genitive

1. o prekidu

The preposition o usually means about and takes the locative case.

• prekid = interruption
• o prekidu = about the interruption

2. opskrbe

Here, opskrbe is genitive singular of opskrba = supply.

So:

• prekid opskrbe = interruption of supply
• upozorenje o prekidu opskrbe = warning about the interruption of supply

This is very common in Croatian:

• kraj filma = end of the film
• početak sata = beginning of the lesson
• prekid opskrbe = interruption of supply

In this sentence, ugasite is an imperative: extinguish, turn off.

It is the 2nd person plural imperative of ugasiti.

So it can mean:

• you all extinguish
• extinguish when speaking politely to one person
• extinguish when giving an instruction to more than one person

Croatian often uses the 2nd person plural imperative in:

• instructions
• warnings
• formal notices
• polite commands

So ugasite svijeću means:

• Extinguish the candle

Although ugasite can look like a present-tense form, in this kind of notice it is understood as an instruction, so it is read as an imperative.

Because svijeću is in the accusative singular, which is used for the direct object.

• svijeća = candle (nominative singular)
• ugasite svijeću = extinguish the candle

Since the candle is the thing being extinguished, Croatian uses the accusative.

For many feminine nouns ending in -a, the accusative singular ends in -u:

• soba → sobu
• svijeća → svijeću
• knjiga → knjigu

So:

• svijeća gori = the candle is burning
• ugasite svijeću = extinguish the candle

Provjetriti means to air out, to ventilate, or to let fresh air into a room.

So:

• provjetrite sobu = air out the room / ventilate the room

Again, sobu is accusative singular because it is the direct object:

• soba = room
• sobu = room (as object)

This verb is often used in everyday practical instructions:

• Provjetrite prostoriju. = Ventilate the room.
• Treba provjetriti stan. = The apartment needs airing out.

They are both imperatives in the 2nd person plural.

• ugasite = extinguish / turn off
• provjetrite = air out / ventilate

This is the standard form used in:

• instructions
• safety notices
• official recommendations
• polite commands

So the sentence sounds like a formal instruction, which is exactly what you would expect in a safety or utility notice.

It can be either, depending on context.

The 2nd person plural imperative in Croatian is used for:

1. more than one person

   • You all, extinguish the candle and ventilate the room.

2. one person politely/formally

   • like formal you in many European languages

In public notices, manuals, and warnings, this plural/formal form is very common even when no specific person is being addressed.

This is about aspect, which is very important in Croatian.

Croatian verbs usually come in pairs:

• imperfective: focuses on the process, repetition, or duration
• perfective: focuses on a completed action

Here:

• ugasiti is perfective
• provjetriti is also perfective

That makes sense because the notice is telling you to perform complete, one-time actions:

• extinguish the candle
• ventilate the room

It is not talking about an ongoing process like be extinguishing or keep ventilating. It is telling you to do the action and complete it.

Compare:

• gasiti = to be putting out / to put out repeatedly
• ugasiti = to put out completely, turn off

It can mean both, depending on the object.

For example:

• ugasiti svijeću = extinguish a candle
• ugasiti svjetlo = turn off the light
• ugasiti motor = turn off the engine
• ugasiti cigaretu = stub out / extinguish a cigarette

So the core idea is cause something burning, shining, or running to stop.

Croatian has no articles like English a/an/the.

So nouns like:

• upozorenja
• svijeću
• sobu

do not need separate words for a or the.

Whether the meaning is:

• a warning
• the warning
• the room
• a room

depends on context.

That is why one Croatian sentence can sometimes be translated into English in more than one natural way.

The given word order is natural and clear, especially for an instruction:

• Nakon upozorenja o prekidu opskrbe ugasite svijeću i provjetrite sobu.

Croatian word order is more flexible than English because case endings show grammatical relationships. But the original order is good because it presents the information in a logical sequence:

1. when to do it: nakon upozorenja o prekidu opskrbe
2. what to do: ugasite svijeću i provjetrite sobu

You could move parts around, but in a practical notice this order is the most straightforward.

Sobu is accusative singular of soba.

• soba = room
• sobu = room (as direct object)

It is accusative because it is the thing affected by the action:

• provjetrite sobu = ventilate the room

This matches the same pattern as:

• otvorite prozor = open the window
• zatvorite vrata = close the door
• očistite sobu = clean the room

Here are the main dictionary forms:

• nakon = after
• upozorenje = warning
• o = about
• prekid = interruption
• opskrba = supply
• ugasiti = to extinguish / turn off
• svijeća = candle
• provjetriti = to air out / ventilate
• soba = room

This is useful because many forms in the sentence are changed by case or verb form:

• upozorenja ← upozorenje
• prekidu ← prekid
• opskrbe ← opskrba
• svijeću ← svijeća
• sobu ← soba

It is common, but it sounds a bit more formal or technical than some everyday English equivalents.

Opskrba means supply, often in contexts like:

• water supply
• gas supply
• electricity supply
• supply of goods

Examples:

• opskrba plinom = gas supply
• opskrba vodom = water supply
• prekid opskrbe = supply interruption / outage

In a notice, opskrba is very natural.

Yes. Because of the grammar, the phrase clearly means:

• warning about an interruption of supply

It does not mean:

• after the interruption itself

That is because:

• nakon governs upozorenja
• o governs prekidu
• opskrbe depends on prekidu

So the structure is:

• nakon [upozorenja [o [prekidu opskrbe]]]

In other words, the action happens after the warning, not after the interruption.

Yes, very much so.

This sentence has several features typical of official or safety language:

• formal, concise wording
• 2nd person plural imperatives
• technical noun phrases like prekid opskrbe
• direct instructions without extra politeness markers

That makes it sound like something from:

• a utility company notice
• a safety manual
• an emergency instruction
• a public warning

So for a learner, it is a good example of practical formal Croatian.