Prije škole dječak mora zakopčati jaknu i zavezati vezice na tenisicama.

Because prije usually requires the genitive case.

• škola = nominative singular
• škole = genitive singular

So:

• prije škole = before school

This is a very common pattern in Croatian:

• prije ručka = before lunch
• prije posla = before work
• prije sata = before the class / before an hour, depending on context

Dječak is the subject of the sentence, so it stands in the nominative singular.

• dječak = boy

Croatian usually uses the nominative for the person or thing doing the action. Here, the boy is the one who must button and must tie, so dječak stays in nominative.

Mora is the 3rd person singular present tense of morati, meaning must / has to.

So:

• ja moram = I must
• ti moraš = you must
• on/ona mora = he/she must

In this sentence:

• dječak mora... = the boy must...

Croatian often uses morati + infinitive, just like English uses must + base verb or have to + verb.

Because they depend on mora.

The pattern is:

• morati + infinitive

So:

• mora zakopčati = must button up
• mora zavezati = must tie

This is similar to English:

• He must go
• He must eat
• He must tie his shoelaces

In Croatian, after morati, the next verb normally appears in the infinitive.

Zakopčati is the perfective verb, while kopčati is the imperfective partner.

Very roughly:

• kopčati = to be buttoning / to button in a general or repeated sense
• zakopčati = to button up completely, as a completed action

In this sentence, the completed action is what matters: the boy must get the jacket buttoned up, so zakopčati is natural.

This is a very common Croatian pattern: one verb focuses on the process or habit, and the other on completion.

Because jakna is the direct object of zakopčati, so it takes the accusative singular.

• jakna = nominative
• jaknu = accusative

So:

• zakopčati jaknu = to button up the jacket

This is very common with feminine nouns ending in -a:

• knjiga → knjigu
• torba → torbu
• jakna → jaknu

Vezice here means shoelaces.

The singular is:

• vezica = lace / little tie / string, depending on context

The plural is:

• vezice = laces

In this sentence, because we are talking about the laces on sneakers, vezice means shoelaces.

Because vezice is the direct object, and na tenisicama tells you where those laces are.

So the structure is:

• zavezati vezice = tie the laces
• na tenisicama = on the sneakers

Together:

• zavezati vezice na tenisicama = tie the shoelaces on the sneakers

Croatian often uses this kind of phrase to specify location or attachment.

Because na here is used with the locative case to mean on or on the surface of / on something worn.

The noun is:

• tenisice = sneakers

Its locative/instrumental plural form is:

• tenisicama

So:

• na tenisicama = on the sneakers

Compare:

• na stolu = on the table
• na cipelama = on the shoes
• na tenisicama = on the sneakers

Yes, in everyday speech Croatian speakers may say things like zavezati tenisice, meaning tie your shoes/sneakers. That is a natural shorthand.

But zavezati vezice na tenisicama is more explicit: it literally mentions the laces. So the sentence is focusing on the exact action.

You can think of it like the difference between:

• tie your shoes
• tie the laces on your sneakers

Both are natural, but the second is more specific.

Croatian often leaves possession unstated when it is obvious from context.

In English, we usually say:

• button his jacket
• tie his shoelaces

In Croatian, if it is clear that the jacket and shoelaces belong to the boy, you can simply say:

• zakopčati jaknu
• zavezati vezice na tenisicama

If you want to make possession explicit, you could say:

• zakopčati svoju jaknu = button his own jacket
• zavezati svoje vezice = tie his own laces

But that is not necessary here.

Yes, Croatian word order is fairly flexible.

This version puts Prije škole first, which emphasizes the time frame:

• Prije škole dječak mora zakopčati jaknu i zavezati vezice na tenisicama.

You could also say:

• Dječak mora prije škole zakopčati jaknu i zavezati vezice na tenisicama.

Both are grammatical. The difference is mostly about focus and style, not basic meaning.

Croatian often places time expressions early in the sentence, especially when they set the scene.

Yes. I is the standard Croatian word for and.

Here it joins the two infinitives:

• zakopčati jaknu
• zavezati vezice na tenisicama

So:

• zakopčati jaknu i zavezati vezice na tenisicama
• button the jacket and tie the shoelaces on the sneakers

Yes, exactly.

Both zakopčati and zavezati are perfective, which fits well because the sentence is about actions that should be completed before school.

The idea is not just to be buttoning or to be tying, but to finish buttoning and finish tying.

That is why perfective verbs sound natural here. If you used imperfective verbs, the meaning would shift toward process, habit, or repeated action depending on context.

A good way is to read it in parts:

• Prije škole = before school
• dječak mora = the boy must
• zakopčati jaknu = button up the jacket
• i zavezati vezice na tenisicama = and tie the laces on the sneakers

So the grammar becomes much easier if you see it as:

• time expression
• subject + modal verb
• infinitive phrase
• and + second infinitive phrase

This chunking method is very helpful when reading Croatian.