Learn Hardcore Polish: Jeśli winda jest zepsuta, trzeba użyć schodów. - If the elevator is broken, one has to use the stairs.

jeśli means if in Polish. It introduces a conditional clause. You can also use jeżeli; both mean the same, but: • jeśli is more common in everyday speech.
• jeżeli can sound slightly more formal or bookish.

What is the gender and case of winda, and why is it in this form?

winda is a feminine noun, singular, in the nominative case. In the clause Jeśli winda jest zepsuta it functions as the subject of the verb jest.

What is zepsuta and why does it end with -a?

zepsuta is the feminine singular past passive participle of the verb zepsuć (to break). As a participial adjective, it agrees in gender (feminine), number (singular) and case (nominative) with its noun (winda).

Why is jest used in winda jest zepsuta? Could we omit it?

jest is the 3rd-person singular form of być, meaning to be, and links the subject (winda) with the adjective (zepsuta). Without jest, the sentence would be ungrammatical in standard Polish. You need a copula to say the elevator is broken.

What does trzeba mean, and why is there no explicit subject?

trzeba is an impersonal modal word meaning one must or it is necessary to. It doesn’t have a specific subject; instead, it implies a general obligation. The structure is always trzeba + infinitive, without a personal pronoun.

Why does użyć (to use) take schodów in the genitive case?

The verb użyć governs the genitive case for its object. So you say użyć czego? and the answer is schodów (genitive plural of schody).

What is the nominative form of schodów and how would you decline schody in plural?

The nominative plural is schody. The genitive plural is schodów.
A quick declension of schody (stairs) in plural:
• Nom. schody
• Gen. schodów
• Dat. schodom
• Acc. schody
• Inst. schodami
• Loc. schodach

Could I say po schodach (instrumental) instead of użyć schodów?

You can use po schodach but with a different verb, e.g. iść po schodach (to go up/down the stairs). po + instrumental expresses movement along. Using użyć schodów (genitive) focuses on making use of the stairs as an alternative.

Could I rephrase Jeśli winda jest zepsuta as Jeśli winda się zepsuje?

Yes. zepsuć się is perfective (to break down), so Jeśli winda się zepsuje means if the elevator breaks down. The original uses jest zepsuta to describe its current broken state, while się zepsuje emphasizes the action of breaking in the future.

Can I replace trzeba with musisz and what changes?

Yes, you can say Musisz użyć schodów (you must use the stairs), but:
• trzeba is impersonal (one must), neutral.
• musisz is second person (you must), direct, and requires the subject ty (implied). The tone becomes more personal or commanding.