Nakon groma moja kći zatvara prozor i sjedi uz mene.

Because nakon is a preposition that normally takes the genitive case.

• grom = thunder, a thunderclap
• groma = genitive singular of grom

So:

• nakon groma = after the thunder / after a thunderclap

This is a pattern worth memorizing:

• nakon kiše = after the rain
• nakon škole = after school
• nakon ručka = after lunch

Grom usually means thunder or a thunderclap, not lightning.

If you want lightning, the usual word is munja.

So:

• grom = thunder / thunderclap
• munja = lightning

In this sentence, nakon groma suggests after a clap of thunder.

Moja kći is in the nominative singular because it is the subject of the sentence.

• moja = my
• kći = daughter

So moja kći means my daughter.

The verb agrees with this subject:

• moja kći zatvara
• moja kći sjedi

Because kći is feminine singular, the possessive adjective is also feminine singular: moja.

Croatian has no articles like a or the.

English says:

• my daughter
• the window
• a window

Croatian simply uses the noun, and the exact meaning depends on context:

• moja kći = my daughter
• prozor = window / the window / a window

Here, prozor is understood from context as the window.

Because prozor is the direct object of zatvara, and with this verb the direct object is normally in the accusative case.

For masculine inanimate nouns, the accusative singular is often the same as the nominative singular:

• nominative: prozor
• accusative: prozor

So:

• zatvara prozor = closes the window

Compare with a feminine noun, where the form often changes more clearly:

• zatvara knjigu = closes/puts away the book

This is mainly about aspect and sometimes tense usage.

• zatvarati = imperfective verb, focusing on the process, repeated action, or ongoing action
• zatvoriti = perfective verb, focusing on completion

Zatvara is the 3rd person singular present of zatvarati.

So moja kći zatvara prozor can suggest:

• she is closing the window
• she closes the window

By contrast, zatvori can be:

• present of a perfective verb, often with future meaning in some contexts
• also an imperative form in other contexts, depending on the sentence

For learners, the simplest takeaway is:

• zatvara = is closing / closes
• zatvorila je = closed
• zatvorit će = will close

Because the correct verb is sjediti = to sit.

Its present tense forms include:

• ja sjedim = I sit / I am sitting
• ti sjediš = you sit
• on/ona sjedi = he/she sits

So:

• sjedi uz mene = sits next to me / is sitting beside me

Be careful not to confuse it with similar-looking words.

Uz here means next to, beside, or close by.

Mene is the form of ja used after many prepositions.

So:

• uz mene = beside me / next to me

This phrase often suggests physical closeness, sometimes emotional comfort too, depending on context.

Examples:

• Sjedi uz mene. = Sit next to me.
• Pas leži uz mene. = The dog is lying beside me.

Because prepositions in Croatian require specific cases, and pronouns change form depending on case.

The basic pronoun is:

• ja = I

But after the preposition uz, you need the accusative form:

• mene = me

So:

• uz mene = next to me

Other examples:

• vidi mene = sees me
• za mene = for me
• na mene = onto me / at me

Because nakon groma gives the time context, and Croatian often uses the present tense to describe actions happening in that situation.

So the sentence means something like:

• After a thunderclap, my daughter closes the window and sits beside me.
• or, in natural English, After the thunder, my daughter closes the window and sits next to me.

Depending on the wider context, this can sound like:

• a habitual action
• a vivid narration
• a description of what happens in that moment

Croatian present tense is often used a bit more flexibly than English learners expect.

Yes. Croatian word order is relatively flexible because case endings show grammatical roles.

The neutral order here is:

• Nakon groma moja kći zatvara prozor i sjedi uz mene.

But you could also hear variations such as:

• Moja kći nakon groma zatvara prozor i sjedi uz mene.
• Moja kći zatvara prozor i nakon groma sjedi uz mene.
  This changes the emphasis and may sound less natural depending on the intended meaning.

The original sentence is natural because it first sets the time frame with nakon groma.

Yes. In this sentence, i simply connects two verbs with the same subject:

• zatvara prozor = closes the window
• sjedi uz mene = sits beside me

So:

• moja kći zatvara prozor i sjedi uz mene = my daughter closes the window and sits beside me

Since the subject moja kći applies to both verbs, it only needs to be said once.

Yes, in many contexts you could.

All of these can mean next to me / beside me:

• uz mene
• pokraj mene
• pored mene

But there are slight differences in feel:

• uz mene often suggests very close physical proximity, almost right by my side
• pokraj mene and pored mene are also common and often feel a bit more neutral

So sjedi uz mene is perfectly natural, especially if the idea is that she comes close after hearing thunder.