Якщо мережа повільна, я не можу відкрити файл.

Because якщо мережа повільна is a subordinate clause introduced by якщо (if). In Ukrainian, subordinate clauses are normally separated from the main clause with a comma.

So the sentence structure is:

• Якщо мережа повільна = if the network is slow
• я не можу відкрити файл = I can’t open the file

You would also keep the comma if you reverse the order:

• Я не можу відкрити файл, якщо мережа повільна.

Both are correct.

Yes. Якщо is the standard word for if in conditional sentences.

Examples:

• Якщо буде дощ, ми не підемо. = If it rains, we won’t go.
• Якщо ти втомився, відпочинь. = If you’re tired, rest.

In everyday speech, you may also hear коли in some contexts where English would use if, especially for more general or repeated situations, but якщо is the clearest basic translation of if.

Because повільна has to agree with мережа.

• мережа is a feminine singular noun
• adjectives must match the noun in gender, number, and case

So:

• masculine: повільний
• feminine: повільна
• neuter: повільне
• plural: повільні

Since мережа is feminine singular, the correct form is повільна.

Мережа is in the nominative singular.

That is because it is the subject of the clause мережа повільна = the network is slow.

In this kind of sentence, the thing being described is usually in the nominative:

• Файл великий. = The file is large.
• Мережа повільна. = The network is slow.

In the present tense, Ukrainian usually leaves out the verb to be.

So where English says:

• The network is slow

Ukrainian simply says:

• Мережа повільна

This is completely normal.

In other tenses, forms of бути do appear:

• Мережа була повільна. = The network was slow.
• Мережа буде повільна. = The network will be slow.

Yes, Ukrainian often omits subject pronouns because the verb ending already shows the person.

• можу already means I can
• so не можу відкрити файл can already mean I can’t open the file

Adding я is still correct. It can:

• make the subject clearer
• add slight emphasis
• sound more explicit

So both are possible:

• Якщо мережа повільна, не можу відкрити файл.
• Якщо мережа повільна, я не можу відкрити файл.

The version with я is especially helpful for learners because it is very clear.

Не можу means cannot / am not able to.

It is made of:

• не = not
• можу = I can

The verb is могти = to be able to / can.

Some present-tense forms are:

• я можу = I can
• ти можеш = you can
• він/вона може = he/she can
• ми можемо = we can
• ви можете = you can
• вони можуть = they can

With negation:

• я не можу = I cannot
• вона не може = she cannot

In Ukrainian, не is written separately from the verb here.

After могти (can / to be able to), Ukrainian uses an infinitive:

• можу відкрити = can open

So the structure is:

• я не можу + infinitive

Examples:

• Я можу читати. = I can read.
• Я не можу знайти документ. = I can’t find the document.
• Ми не можемо відкрити файл. = We can’t open the file.

This is a question of aspect.

• відкрити = perfective infinitive
• відкривати = imperfective infinitive

In this sentence, відкрити is natural because it refers to a single completed result: open the file successfully.

So:

• не можу відкрити файл = I can’t open the file / I can’t get the file open

If you used відкривати, it would sound more like:

• inability in a repeated/habitual sense
• focus on the process rather than the completed result

For a learner, the simplest rule here is:

• when you mean manage to open, відкрити is very natural

Because файл is the accusative singular, and for inanimate masculine nouns, the accusative usually looks the same as the nominative.

So:

• nominative: файл
• accusative: файл

The word is in the accusative because it is the direct object of відкрити:

• відкрити що? — файл

Compare this with animate masculine nouns, where accusative often matches genitive:

• Я бачу брата. = I see my brother.

But with an inanimate noun:

• Я бачу файл. = I see the file.

Yes. Ukrainian word order is more flexible than English.

These are both correct:

• Якщо мережа повільна, я не можу відкрити файл.
• Я не можу відкрити файл, якщо мережа повільна.

The difference is mainly about emphasis and flow:

• starting with Якщо мережа повільна emphasizes the condition first
• starting with Я не можу відкрити файл emphasizes the main statement first

The original version is very natural.

Not necessarily. Мережа literally means network.

Depending on context, it could mean:

• a computer network
• a mobile network
• an internet connection
• a network in a broader technical sense

In this sentence, most people would understand it as something like:

• the network connection is slow

If you specifically wanted internet, you could say інтернет, but мережа is perfectly natural in technical contexts.

Because Ukrainian has no articles like English a/an/the.

So:

• мережа can mean a network or the network
• файл can mean a file or the file

The exact meaning depends on context.

This is very normal in Ukrainian. Learners from English often want to add an article somehow, but Ukrainian simply does not use one.

A natural rhythm would often be:

ЯКЩО мережа повіЛЬНА, я не МОжу відКРИти ФАЙЛ.

You do not need to memorize a special stress pattern for the whole sentence, but it helps to know the word stresses:

• яКЩО
• меРЕжа
• повіЛЬна
• моЖУ
• відКРИти
• файл (one syllable)

Sentence stress can move depending on what you want to emphasize, but this is a natural neutral reading.

Yes. The Ukrainian sentence can work in both ways, depending on context:

• a specific current situation: If the network is slow, I can’t open the file.
• a general repeated fact: If the network is slow, I can’t open the file.

Ukrainian often relies on context to show whether something is:

• happening right now
• generally true
• repeated

So the same sentence can cover both meanings unless the wider context makes one interpretation clearer.