Learn Hardcore Polish: Właściciel sklepu zamyka drzwi po pracy. - The store owner closes the door after work.

właściciel means “owner.” When you say “owner of something,” Polish uses the genitive case: właściciel czego? → sklepu (“of the shop”). Thus sklepu is genitive singular, showing possession.

Why is drzwi always in plural, and how do I know it’s the direct object of zamyka?

drzwi is a pluralia tantum noun (it only exists in the plural form). Here it’s the direct object of zamyka, so it takes the accusative. For many inanimate nouns in Polish, the nominative plural and accusative plural look the same, which is why drzwi doesn’t change form.

Why is the verb zamyka used instead of the perfective form zamknie?

zamyka is the imperfective present tense, used for habitual or repeated actions: “he closes (doors) every day after work.” If you describe a single, completed future action, you’d use the perfective zamknie:
• Właściciel sklepu zamknie drzwi po pracy. (“The owner will close the doors after work.”)

Why is there no article like the or a in the sentence?

Polish doesn’t have articles. Whether you mean “the owner” or “a store owner” is understood from context, or you can add demonstratives (ten właściciel = “that/the owner,” jakiś właściciel = “some/a certain owner”).

What case is po pracy, and why is pracy in the locative rather than the genitive?

After time expressions, the preposition po requires the locative case. Praca in the locative is pracy, so po pracy literally means “after (the) work.” (Note: locative forms often look like genitive for many feminine nouns.)

Is the word order fixed? Could I say Po pracy właściciel sklepu zamyka drzwi?

Polish word order is quite flexible. Po pracy właściciel sklepu zamyka drzwi is perfectly correct. Starting with Po pracy simply puts slight emphasis on the time (“It’s after work that the owner closes the doors”).

How do you pronounce ł, sz, and rz in this sentence?

• ł is pronounced like English w (so właściciel sounds roughly vwah-sh-CHEE-el).
• sz is like English sh in “ship.”
• rz (and the cluster drz) is like English zh in “measure.”
• The letter w in drzwi is pronounced like English v, making drzwi sound like DZH-v’ee.

How would I say “one door” in Polish since drzwi is always plural?

You use a plural form of one: jedne drzwi means “one door.” If you want to stress it’s a single door, you can also say pojedyncze drzwi, but jedne drzwi is the standard way.