Learn Hardcore Polish: Przestaję czytać książkę, gdy robi się ciemno. - I stop reading the book when it gets dark.

Przestaję is the 1st person singular present tense of the imperfective verb przestawać, meaning “I stop” (i.e. I’m stopping). We use the present tense to show either a habitual action (“I stop reading every day when it gets dark”) or an action happening right now. The imperfective aspect highlights the ongoing process of stopping rather than the fact that the stopping is already completed.

Why is czytać in the infinitive form instead of a finite verb form?

In Polish, when one verb governs another, the second verb stays in the infinitive. Verbs like przestawać are followed by an infinitive to indicate what action is being stopped. That’s why you say przestaję czytać (“I stop reading”) rather than trying to conjugate czytać.

Why is książkę in the accusative case?

Czytać is a transitive verb and takes a direct object. In Polish, direct objects are marked with the accusative case. Książka (book) is a feminine noun, so its accusative singular form is książkę.

What does the phrase gdy robi się ciemno mean?

Literally, gdy means “when,” robi się (a reflexive form of robić) means “it becomes,” and ciemno means “dark.” Altogether, gdy robi się ciemno = “when it gets dark” (when it becomes dark).

Why use robi się ciemno instead of simply jest ciemno?

Both are correct, but jest ciemno means “it is dark” (a static state), while robi się ciemno emphasizes the transition or change (“it’s getting dark”). The reflexive construction robić się + adjective highlights the process of becoming.

Why is there a comma before gdy?

In Polish, subordinate clauses introduced by conjunctions like gdy are separated from the main clause with a comma. Here, gdy robi się ciemno is a time clause that follows the main clause, so you place a comma before gdy.

Can I replace gdy with kiedy, and does the comma stay?

Yes. Kiedy also means “when” and works the same way:
Przestaję czytać książkę, kiedy robi się ciemno.
You still need the comma before kiedy, since it begins a subordinate clause.

Is the word order przestaję czytać książkę the only option?

Polish word order is quite flexible, but the most neutral phrasing is przestaję czytać książkę. You could say przestaję książkę czytać, but it sounds marked or poetic. Generally, infinitive + object is the standard order after verbs like przestawać.

What part of speech is ciemno, and why doesn’t it change form?

Here ciemno functions as an indeclinable adverb (or predicative word) meaning “darkly”/“dark.” In expressions of weather or light conditions (jest ciepło, robi się jasno, jest ciemno) these adverbs stay invariable and don’t agree in gender or number.