Wczoraj nie mogłam przeczytać całej powieści, bo wieczorem musiałam jeszcze zrobić przelew.

Because the speaker is female.

In the Polish past tense, verbs agree with the gender of the person speaking:

• mogłam, musiałam = said by a woman
• mogłem, musiałem = said by a man

So a male speaker would say:

• Wczoraj nie mogłem przeczytać całej powieści, bo wieczorem musiałem jeszcze zrobić przelew.

This is one of the first things English speakers notice, because English past tense does not show the speaker’s gender.

Because przeczytać is the perfective form, and it focuses on completing the action.

• czytać = to read, to be reading, to read in general
• przeczytać = to read something all the way through, to finish reading

Here the sentence is about not managing to finish the whole novel, so przeczytać is the natural choice.

Compare:

• Nie mogłam czytać. = I couldn’t read / I wasn’t able to read at all.
• Nie mogłam przeczytać całej powieści. = I couldn’t finish reading the whole novel.

So the perfective verb matches the idea of a completed result.

Because after negation, a direct object in Polish is very often put in the genitive.

Without negation, you would expect the accusative:

• Mogłam przeczytać całą powieść. = I was able to read the whole novel.

With negation:

• Nie mogłam przeczytać całej powieści.

Here:

• cała powieść = nominative
• całą powieść = accusative
• całej powieści = genitive

This is a very important Polish pattern: negated verbs often take the genitive instead of the accusative.

Primarily, it is there because of negation.

The basic contrast is:

• przeczytać całą powieść = to read the whole novel
• nie móc przeczytać całej powieści = not be able to read the whole novel

So the form całej powieści is mainly grammatical here.

That said, the phrase still keeps the meaning of the whole novel. The sentence does not mean that the speaker read none of it; it means she did not manage to get through all of it.

Here jeszcze means something like still, yet, or in addition.

• musiałam jeszcze zrobić przelew = I still had to make a bank transfer / I had one more thing to do: make a bank transfer

It suggests that this was an extra task that remained to be done.

Very often jeszcze adds the feeling of there was still something left.

Compare:

• Musiałam zrobić przelew. = I had to make a bank transfer.
• Musiałam jeszcze zrobić przelew. = I still had to make a bank transfer / I also had to make a bank transfer.

Yes, and that is the normal Polish expression.

In Polish, a bank transfer is commonly expressed with:

• zrobić przelew = to make a bank transfer
• wykonać przelew = to execute a bank transfer, a bit more formal

So even though English might say make a transfer or do a bank transfer less often in everyday speech, Polish naturally uses zrobić here.

Also:

• przelew = bank transfer

So zrobić przelew is a very common collocation.

Wieczorem is an instrumental form used adverbially.

The base noun is:

• wieczór = evening

But in time expressions, Polish often uses special forms like:

• rano = in the morning
• wieczorem = in the evening
• nocą = at night

So wieczorem means in the evening.

You do not need to think of it as a literal instrumental every time you use it; it is best learned as a fixed adverbial time expression.

Yes, ponieważ would also work, but bo is more common in everyday speech.

• bo = because
• ponieważ = because / since, slightly more formal or written
• gdyż = because, more formal/bookish

So:

• ..., bo wieczorem musiałam jeszcze zrobić przelew.
  is natural and conversational.

You could also say:

• ..., ponieważ wieczorem musiałam jeszcze zrobić przelew.

That sounds fine, just a bit more formal.

This is an important distinction.

• Nie mogłam przeczytać całej powieści. = I couldn’t read/finish the whole novel.
  This emphasizes lack of ability, opportunity, or time.
• Nie przeczytałam całej powieści. = I didn’t read/finish the whole novel.
  This simply states that it did not happen.

In your sentence, the second clause gives a reason:

• ..., bo wieczorem musiałam jeszcze zrobić przelew.

So nie mogłam przeczytać fits very well, because it means the speaker was prevented from finishing it.

Yes. Polish word order is fairly flexible, although some orders sound more natural than others.

The original sentence is neutral and natural:

• Wczoraj nie mogłam przeczytać całej powieści, bo wieczorem musiałam jeszcze zrobić przelew.

You could also say:

• Nie mogłam wczoraj przeczytać całej powieści, bo wieczorem musiałam jeszcze zrobić przelew.
• Wczoraj nie mogłam przeczytać całej powieści, bo jeszcze wieczorem musiałam zrobić przelew.
• Bo wieczorem musiałam jeszcze zrobić przelew, wczoraj nie mogłam przeczytać całej powieści.
  This is possible, but less neutral and more marked.

Changing word order usually changes emphasis rather than core meaning.

Because wczoraj only tells you when something happened; it does not replace the past tense.

Polish, like English, still needs past-tense verb forms:

• wczoraj = yesterday
• mogłam, musiałam = past tense

So the structure is normal: a past-time adverb plus past-tense verbs.

Yes, but it would slightly change the emphasis.

Your sentence has:

• Wczoraj ... = yesterday, for the whole main situation
• wieczorem ... = specifically in the evening, for the reason clause

So it means roughly: yesterday I couldn’t finish the novel, because in the evening I still had to make a transfer.

If you said:

• Wczoraj wieczorem nie mogłam przeczytać całej powieści...

that would put the reading problem specifically in yesterday evening.

The original version is a little broader: the whole day was yesterday, and the evening task explains why the reading did not get finished.

No. Powieść specifically means novel.

Compare:

• książka = book
• powieść = novel

So if the learner already knows the meaning, it is still useful to notice that Polish distinguishes these words clearly, just as English does.

In this sentence:

• cała powieść = the whole novel

That is more specific than just book.