Learn Polish: Gdyby nie ten ratownik, mogłem wczoraj zginąć! - If it weren't for this rescuer, I could have died yesterday!

The phrase gdyby nie (if it weren't for) is a fixed expression in Polish that directly takes the Nominative case. You don't need an equivalent to the preposition "for" or "without" here—just gdyby nie followed directly by the noun in its basic, dictionary form.

The English translation says "could have died," which sounds like a conditional. Why does the Polish sentence use the plain past tense mogłem instead of the conditional mógłbym?

In Polish, to say that something almost happened in the past but didn't, you often use the plain past tense of móc (mogłem or mogłam) rather than the conditional. While mógłbym is also grammatically correct, using the simple past mogłem makes the narrowly avoided danger feel more factual: you were literally in a position where dying was a real possibility.

Why use zginąć for "to die" here instead of the standard word umrzeć?

Umrzeć refers to dying in a general or natural way, like from illness or old age. Zginąć specifically means to die a sudden, unnatural, or violent death, such as in an accident or disaster. Since a rescuer (ratownik) was involved, the speaker was clearly in a sudden life-threatening situation, making zginąć the natural choice.

Does gdyby nie change depending on the tense, like English does with "if it weren't for" versus "if it hadn't been for"?