Learn Hardcore Polish: Trzeba jednak uważać, żeby nie zatrzymać ruchu na wąskim korytarzu. - One should, however, be careful not to stop the movement in the narrow corridor.

Trzeba is an impersonal verb often translated as “one must,” “it’s necessary,” or “you need to.” There is no explicit subject in Polish; the action applies generally. In this context, Trzeba jednak uważać means “However, one must be careful” or “You really have to watch out.”

Why is jednak used here, and what is its function?

Jednak means “however,” “still,” or “after all.” It introduces a contrast or caveat relative to what has been said before. Even if something else was decided or assumed, you still need to be careful. It softens or nuances the obligation:

• “I know we’re in a hurry, jednak trzeba uważać”
• “We’re in a hurry, but we still must be cautious.”

What is the role of żeby in this sentence?

Żeby is a subordinating conjunction used to express purpose or result, similar to “so that” or “in order to” in English. Here it introduces the negative purpose clause żeby nie zatrzymać ruchu: “so that (you) don’t stop traffic.”

Why is zatrzymać in the infinitive form rather than a finite verb form?

After trzeba + żeby, Polish uses the infinitive to express what needs to be done (or not done). You do not conjugate zatrzymać for person or number. The structure is: trzeba + żeby + (nie) + infinitive.

Why is ruchu in the genitive case?

Zatrzymać (“to stop”) is a transitive verb that requires a direct object in the accusative case. However, when you negate a perfective infinitive (here nie zatrzymać), the direct object can shift into the genitive to reinforce the negation. So instead of nie zatrzymać ruch, we say nie zatrzymać ruchu.

Why is na wąskim korytarzu used, and what case is wąskim korytarzu?

• na can govern either the locative or accusative in Polish. Here it describes location (“on the corridor”), so it takes the locative case.
• korytarz (corridor) in locative singular becomes korytarzu, and the adjective wąski takes its locative singular form wąskim.
Together, na wąskim korytarzu means “in (on) the narrow corridor.”

What is the difference between zatrzymać and zatrzymywać?

• zatrzymać is perfective: it refers to completing the action of stopping something once or to its result (“to stop” as a whole action).
• zatrzymywać is imperfective: it describes ongoing or repeated actions (“to be stopping,” “to keep stopping”).
In the context of rules or warnings, you use the perfective (zatrzymać) to talk about the single event you want to avoid.

Could you give a literal word-by-word translation?

Yes. A loose literal translation is:
“One must, however, be careful, so as not to stop traffic on the narrow corridor.”
A more natural English version:
“However, you need to be careful not to block traffic in the narrow corridor.”