More Accusative Prepositions: o, přes, na (motion)

The core accusative prepositions (pro, za, na, mezi…) are covered on the main accusative-prepositions page. This page picks up the trickier extras: the many faces of o (which can govern either the accusative or the locative, with totally different meanings), the crossing-and-via preposition přes, and the motion sense of na — going to an event or destination. These are high-frequency, and the case choice often carries the whole meaning.

o + accusative vs. o + locative

This is the headline. The little word o governs two cases, and the case alone decides what it means.

• o + locative = "about" (a topic): mluvit o něčem "to talk about something." See the locative o of topic.
• o + accusative = "by (a margin)" or "for" (in request/interest verbs): větší o metr "bigger by a meter," požádat o pomoc "to ask for help."

o + accusative: by a margin

When you measure a difference — older by a year, longer by a meter, cheaper by a hundred crowns — Czech uses o + accusative for the amount of the gap.

o + accusative: request, care, interest

A cluster of very common verbs takes o + accusative to mark their object. These are worth memorizing as fixed frames, because the case is not negotiable.

Compare these with o + locative: zajímám se o hudbu ("interested in music," accusative) versus mluvíme o hudbě ("talking about music," locative hudbě). The verb decides which case its o takes, and changing the case changes the meaning, so these patterns repay being learned as whole units. This is part of prepositional verb government.

přes + accusative: across, over, via

Přes always governs the accusative. It covers physical crossing ("across the bridge"), passing over an obstacle, and routing "via" a place. It also extends to "over (a period)" and the concessive "despite."

The "via/through" sense (přes Prahu) is extremely common for journeys and connections — both physical routes and figurative ones ("I got the ticket through a friend," přes kamaráda).

The motion sense of na

Na is a two-case preposition. With the locative it means static location ("on the table," "at the concert" while you're there). With the accusative it marks motion toward a destination or going to an event — and this is the sense English speakers most often get wrong. The fuller acc-vs-loc story is on the na/v/o/za two-case page; here is the practical core.

In each case the verb expresses movement (jdeme, pojďme, jezdíme, polož) and the destination takes the accusative: na koncert, na oběd, na hory, na stůl. Contrast the static locative: Jsme na koncertě ("we're at the concert") versus Jdeme na koncert ("we're going to the concert"). The rule of thumb is direction → accusative, position → locative.

Na + accusative also covers duration — "for (a length of time)": na týden "for a week," na chvíli "for a moment."

v + accusative for days and points in time

While v/ve usually takes the locative for location ("in Prague" v Praze), it takes the accusative in a set of fixed time expressions — days of the week and certain time points.

Here pondělí and poledne are in the accusative (they happen to look the same as the nominative, but the construction is accusative). This is a closed, memorizable set: the days of the week (v pondělí, ve středu, v sobotu) and a couple of fixed daytime points (v poledne "at noon," v noc poetic only). Beware that "at night" is the everyday exception: it is v noci with the locative, not the accusative — so don't generalize the day-of-the-week pattern to it.

Common mistakes

The biggest error is putting o in the wrong case for the meaning — using the locative "about" where the verb wants the accusative "for/in."

A second classic is using the locative after na when the verb is one of motion.

And learners often reach for a different preposition where Czech fixes přes with the accusative.

Key takeaways

• o + accusative = "by (a margin)" (mladší o rok) and "for/in" with request/interest verbs (požádat o pomoc, zajímat se o hudbu); o + locative = "about" a topic (mluvit o hudbě).
• přes + accusative always: across, over, via, throughout (přes most, přes Prahu, přes víkend).
• na + accusative marks motion to a destination/event and duration (na koncert, na hory, na týden); na + locative is static location.
• v + accusative appears in fixed time expressions: v pondělí, v poledne.
• With request, care, and interest verbs, learn the o
  • accusative frame as one unit — the case is non-negotiable.