Tokom preuzimanja proverite patent-zatvarač.

Because tokom requires the genitive case in Serbian.

• Base form: preuzimanje
• Genitive singular: preuzimanja

So tokom preuzimanja literally means during the process of preuzimanje.

This is very common with time expressions:

• tokom dana = during the day
• tokom noći = during the night
• tokom rada = during work / during operation

Preuzimanja is the genitive singular form of the verbal noun preuzimanje.

A verbal noun is a noun made from a verb and used to talk about an action as a thing or process. In English, this is often similar to forms like downloading, taking over, pickup, or retrieval, depending on context.

So here:

• preuzimanje = the act/process of taking over, picking up, downloading, etc.
• preuzimanja = of that act/process, because tokom requires genitive

Proverite is the imperative form of the verb proveriti, meaning check or verify.

More specifically, it is the:

• 2nd person plural imperative

That means it can be used for:

• you all, check
• please check when speaking politely to one person
• general written instructions, like on labels, manuals, or notices

So Serbian often uses this form where English might use:

• Check the zipper
• Please check the zipper
• You should check the zipper

The ending -ite marks the plural / formal imperative for many Serbian verbs.

For proveriti, the imperative forms are:

• proveri = check! (informal singular)
• proverite = check! (plural or polite/formal singular)

This is why instructions in Serbian often use -ite forms: they sound neutral, polite, and standard in public writing.

This is a question of aspect, which is very important in Serbian.

• proveriti = perfective = to check something once and complete the action
• proveravati = imperfective = to be checking / check repeatedly / check from time to time

So:

• proverite means do the check
• proveravajte would suggest keep checking or check repeatedly

In an instruction like this, Serbian usually prefers the perfective imperative when it wants one complete action.

It can be both.

In Serbian, the same form can mean:

• speaking to more than one person
• speaking politely to one person
• giving neutral written instructions

So in a sentence like this, you usually do not need to decide exactly which one it is. It simply sounds like a standard instruction.

It is in the accusative singular, because it is the direct object of proverite.

You are checking what?

• patent-zatvarač

For inanimate masculine nouns in Serbian, the accusative singular is usually the same as the nominative singular.

So:

• nominative: patent-zatvarač
• accusative: patent-zatvarač

That is why the form does not visibly change.

It is a compound noun, and the hyphen shows that the two parts belong together as one lexical item.

• patent
• zatvarač

Together they mean zip fastener / zipper.

For a learner, the important point is that you should treat patent-zatvarač as one noun in the sentence.

Tokom is not extremely formal, but it is a bit more typical of written, neutral, or official-style language.

In everyday speech, people might also use other structures depending on the context, such as:

• za vreme
• u toku
• a clause with dok

But tokom is very common and perfectly normal, especially in instructions and informational text.

Serbian word order is relatively flexible, and the beginning of the sentence often gives the time frame or context first.

So Tokom preuzimanja sets the scene:

• During the process of ...

Then comes the main instruction:

• proverite patent-zatvarač

This ordering is natural in Serbian because it tells the reader when the action should happen before giving the command itself.

Because Serbian has no articles.

English uses a and the, but Serbian normally does not. Definiteness is understood from context.

So patent-zatvarač can mean:

• a zipper
• the zipper

Which one is intended depends on the situation, not on a separate article word.

This is one of the biggest differences between English and Serbian.