Questions & Answers about Ten pociąg kursuje co dwie godziny.
Why is co used here for "every" instead of a form of każdy?
When talking about intervals or frequency in time or space (like "every two hours" or "every five kilometers"), Polish uses co. The word każdy means "each" or "every" when referring to items in a group, like każdy pociąg (every train).
What grammatical case follows co in this time expression?
In distributive frequency phrases, co is followed by the Nominative case. So dwie godziny is exactly how you would say "two hours" as the subject of a sentence. This makes these interval expressions very easy to construct once you know your numbers!
Why does this sentence use kursuje for "runs" instead of biega or jedzie?
The English verb "to run" has many meanings, but the Polish verb biegać strictly means physical running with legs. For vehicles operating on a regular schedule or route, Polish uses the verb kursować. If you said Ten pociąg jedzie, it would just mean the train is driving or traveling right now, rather than describing its scheduled service.
As a quick refresher, why do we say dwie godziny instead of dwa godziny?