Nedostaje mi jedna stranica u dokumentu, pa ne mogu sastaviti cijeli izvještaj.

Because nedostajati takes the person affected in the dative case, not the nominative.

• mi = to me / for me
• So Nedostaje mi jedna stranica literally works like One page is lacking to me.

This is different from English, where we usually say I am missing a page or A page is missing. In Croatian, the grammar is built around the thing that is absent, not around I as the subject.

Nedostaje is the 3rd person singular present of nedostajati.

In this sentence, the grammatical subject is jedna stranica. That is why the verb is singular:

• jedna stranica nedostaje = one page is missing

If the subject were plural, the verb would also be plural:

• Nedostaju mi dvije stranice. = Two pages are missing.

So the pattern is:

• [thing that is missing] + nedostaje/nedostaju + [person in dative]

Because jedna stranica is the subject of the verb nedostaje.

Croatian uses nominative for the subject:

• jedna stranica = nominative singular
• It is the thing that is missing

So even though English might focus on I, Croatian focuses grammatically on the page.

Compare:

• Nedostaje mi jedna stranica.
• Nedostaju mi dvije stranice.

The missing thing stays the subject.

It can do both, depending on context.

Here jedna stranica most naturally means:

• one page

But in some contexts, jedan / jedna / jedno can also add emphasis similar to:

• a certain
• one particular

In this sentence, though, the normal reading is simply one page.

Croatian often does not use an article like English a/the, so sometimes jedna helps make the noun feel more specific or countable.

Because u can take different cases depending on meaning:

• u + accusative = movement into
• u + locative = location in

Here the meaning is in the document, so Croatian uses the locative:

• u dokumentu = in the document

Compare:

• Stavio sam stranicu u dokument. = I put the page into the document.
• Stranica je u dokumentu. = The page is in the document.

Dokumentu is the locative singular of dokument.

The base noun is:

• dokument = document

After u meaning in, masculine nouns often take locative singular in -u:

• u dokumentu
• u gradu
• u uredu

So the ending changes because the preposition requires the locative here.

Pa here means something like:

• so
• and so
• therefore
• which is why

It links the two clauses in a natural, spoken way:

• Nedostaje mi jedna stranica u dokumentu, pa ne mogu sastaviti cijeli izvještaj.
• One page is missing from the document, so I can’t put together the whole report.

It is very common in everyday Croatian and often sounds smoother and less formal than a more explicitly logical connector.

Because mogu + infinitive expresses ability:

• ne mogu sastaviti = I can’t put together / I’m unable to compile

If you said ne sastavim, that would not normally express ability. It would suggest something else depending on context, and it would sound wrong here.

So the sentence is specifically saying:

• because a page is missing, I am not able to complete the report

That is why mogu is needed.

Because sastaviti is the perfective form, and it focuses on completing the action as a whole.

• sastaviti = to put together, compile, complete
• sastavljati = to be putting together, to put together repeatedly/habitually, or to focus on the process

Here the speaker means they cannot successfully finish the report as a complete result:

• ne mogu sastaviti cijeli izvještaj = I can’t compile/put together the whole report

That makes the perfective verb sastaviti the natural choice.

Because it is the direct object of sastaviti.

The infinitive sastaviti takes an object:

• sastaviti izvještaj = to compile a report

Since izvještaj is a masculine inanimate noun, its accusative singular looks the same as the nominative:

• nominative: izvještaj
• accusative: izvještaj

The adjective must agree with the noun, so:

• cijeli izvještaj = accusative singular masculine inanimate

Cijeli means whole / entire.

So:

• sastaviti izvještaj = to compile the report / a report
• sastaviti cijeli izvještaj = to compile the whole report

You could leave it out, but then the sentence would lose the idea that the missing page prevents completion of the report as a whole.

So cijeli adds an important nuance: the report cannot be completed fully.

Yes. Croatian word order is more flexible than English, though some orders sound more neutral than others.

The given sentence is natural and neutral:

• Nedostaje mi jedna stranica u dokumentu, pa ne mogu sastaviti cijeli izvještaj.

But you could also hear things like:

• Jedna mi stranica nedostaje u dokumentu...
• U dokumentu mi nedostaje jedna stranica...

These versions change the emphasis:

• putting u dokumentu earlier emphasizes where
• putting jedna stranica earlier emphasizes what is missing

The original version is a very normal default choice.

Yes. Faliti is very common in everyday speech and often means the same thing here:

• Fali mi jedna stranica.
• Nedostaje mi jedna stranica.

Both mean A page is missing / I’m missing a page.

The difference is mostly style and register:

• nedostajati can sound a bit more neutral or formal
• faliti is very common in conversation

In the sentence you were given, nedostaje fits well, especially in a context involving a document and a report.

Croatian can express this idea in more than one way.

This sentence literally says something like:

• One page is missing in the document

In English, we often prefer from the document, but Croatian often frames it as the page being absent in the document.

You could also hear other phrasings depending on context, but u dokumentu is perfectly natural if the idea is that, when looking at the document, one page is not there.

Yes. Izvještaj is standard Croatian.

A few useful notes:

• Croatian: izvještaj
• Serbian often: izveštaj

So the form with je is exactly what you would expect in standard Croatian.

In business or administrative language, izvještaj is a very common word.