Post la koncerto ni promenas tra la centro kaj serĉas ankoraŭ malfermitan kafejon.

Post means after and works like a normal preposition: it usually takes a full noun phrase.

• post la koncerto = after the concert (a specific, known concert)
• post koncerto would sound like after a concert (in general) or after concerts, and is not how you’d normally say this concrete, one‑time situation.

Because we’re clearly talking about a particular, already known event, Esperanto uses la, just like English uses the in after the concert.

Accusative -n is used for time expressions without a preposition, to show when something happens:

• Lundon mi laboras. – On Monday I work.
• La venontan semajnon mi vojaĝos. – Next week I’ll travel.

But here we have the preposition post:

• post la koncerto – literally after the concert

When there is a preposition (like post, antaŭ, dum, etc.), you don’t use the bare accusative-of-time pattern. The preposition already shows the relationship, so koncerto stays in the normal nominative form.

Esperanto can use the present tense for:

1. Real present time:

   • Nun ni promenas tra la centro. – Now we are walking through the center.

2. Planned or very near future, especially when it’s clearly about a schedule or immediate plan, like in your sentence:

   • Post la koncerto ni promenas… – After the concert we walk…
     (meaning: that’s the plan / that’s what we do next)

You can also say:

• Post la koncerto ni promenos tra la centro kaj serĉos…

That emphasizes the futurity more clearly. Both are grammatically correct; the choice is stylistic. Using the present for a near-future plan is very natural in Esperanto, similar to English We’re going to walk… or We walk afterward.

• post = a preposition meaning after
  It needs something after it:

  • post la koncerto – after the concert
  • post la manĝo – after the meal

• poste = an adverb meaning afterwards, later
  It stands on its own:

  • Ni iros al kafejo poste. – We’ll go to a café later / afterwards.

In your sentence we have a noun phrase (la koncerto), so we need the preposition post, not the adverb poste.

• tra means through, across – it emphasizes movement across the interior of something:

  • Ni promenas tra la parko. – We walk through the park (across it).
  • La rivero fluas tra la urbo. – The river flows through the city.

• en means in, inside (into) and focuses on being in or going into:

  • Ni promenas en la parko. – We walk in the park (inside it, not necessarily across).
  • Ni eniras en la urbon. – We enter into the city.

In tra la centro, the idea is moving through the downtown area, not just being somewhere within it.

There are two main uses of -n:

1. Direct object of the verb.
2. Directional meaning with certain prepositions (showing motion to some place), especially with:
   • en, sur, sub, super, antaŭ, malantaŭ, inter, apud, trans, ĉirkaŭ, etc.
   • Example: en la urbon = into the city (motion toward), vs. en la urbo = in the city (location).

The preposition tra already inherently expresses movement through something. You don’t normally add an extra accusative -n for direction here; tra la centro clearly means “through the center”.

So:

• tra la centro – correct and standard: through the center
• tra la centron – possible but unusual and unnecessary; most speakers just say tra la centro.

In many contexts, la centro means the (city) center, downtown, even without saying urbo:

• Mi loĝas proksime de la centro. – I live near the downtown.

We use la because it’s a specific, context‑known place: the center of the city we’re in / talking about. It’s understood, just like English says the center or the city center.

Ankoraŭ can mean both still and yet, depending on context:

• Li ankoraŭ laboras. – He still works / is still working.
• Ĉu vi ankoraŭ ne finis? – Have you not finished yet?

In your sentence:

• ankoraŭ malfermitan kafejon

means “a café that is still open” – i.e., it’s late and many cafés have already closed; you’re looking for one that is yet / still open.

So the nuance is: “We’re searching for a café that hasn’t closed yet.”

The default position for adverbs like ankoraŭ is right before the word they modify.

• ankoraŭ malfermitan kafejon
  → “a still-open café”

Reordering is technically possible, but:

• malfermitan ankoraŭ kafejon sounds odd and unclear.
• malfermitan kafejon ankoraŭ would more likely be understood as modifying the whole clause (still a café that is open), and is not the usual, clean way to say it.

So ankoraŭ malfermitan kafejon is the natural order: the adverb directly modifying malfermitan.

Both forms exist but have slightly different focuses:

• malferma = open as a state / quality
  (adjective from the root malferm-)
• malfermita = opened / having been opened – a past participle, focusing on the result of an opening action

In practice:

• malferma pordo – a door that is open (state)
• malfermita pordo – a door that has been opened (result of the action “to open”)

For cafés and shops, many speakers use malfermita in this “open/closed (for business)” sense:

• malfermita kafejo – a café that is (for now) open (i.e., it has been opened for business and not yet closed)
• fermita kafejo – a café that is closed

You could hear malferma kafejo too; it’s understandable. But ankoraŭ malfermitan kafejon nicely matches the idea that many have already been closed, and you want one still in the “opened” state.

In Esperanto, adjectives agree with their noun in number and case:

• kafejo (sg, nom) → malfermita kafejo
• kafejon (sg, acc) → malfermitan kafejon
• kafejoj (pl, nom) → malfermitaj kafejoj
• kafejojn (pl, acc) → malfermitajn kafejojn

So, since kafejon is accusative singular (direct object), malfermitan must also be accusative singular.

In casual speech, some people may sometimes drop the -n on adjectives, but correct grammar is to keep the agreement: malfermitan kafejon.

Yes. Serĉi means to search / to look for, and the thing you search for is its direct object:

• Mi serĉas mian amikon. – I’m looking for my friend.
• Li serĉas la butikon. – He’s looking for the shop.

So in your sentence:

• ni … serĉas ankoraŭ malfermitan kafejon
  → we look for a café that is still open

Kafejon is the direct object of serĉas, so it correctly takes the accusative -n.

Normally, no. In Esperanto:

• serĉi ion = to look for something
  The thing you are seeking is the direct object.

Serĉi por io would sound like “to search for the sake of something” or “to search on behalf of something”, which is not what you mean here.

So:

• ✅ serĉi kafejon – to look for a café
• ❌ serĉi por kafejo – not the normal way to say that

In Esperanto, when you join verbs with kaj (and), you normally keep them in the same finite form:

• Ni sidas kaj parolas. – We sit and talk.
• Ŝi kantis kaj dancis. – She sang and danced.

Using an infinitive (serĉi) here would be ungrammatical, because there’s no other verb that needs an infinitive complement. We just have two separate actions:

• Ni promenas tra la centro – We walk through the center
• (ni) serĉas ankoraŭ malfermitan kafejon – (we) look for a café that is still open

Joined:

• Ni promenas tra la centro kaj serĉas ankoraŭ malfermitan kafejon.

Yes. Esperanto word order is quite flexible. You can move post la koncerto as long as you keep the meaning clear:

• Post la koncerto ni promenas tra la centro kaj serĉas… (original)
• Ni post la koncerto promenas tra la centro kaj serĉas…
• Ni promenas tra la centro post la koncerto kaj serĉas…
• Ni promenas post la koncerto tra la centro kaj serĉas…

The most neutral is probably the original, with the time phrase at the beginning, or immediately after ni. Moving it can add slight emphasis, but doesn’t change the core meaning.

Yes, that’s a good alternative and sounds natural:

• Ni promenas tra la centro, serĉante ankoraŭ malfermitan kafejon.

Here, serĉante is the present active participle of serĉi, used adverbially:

• literally: We walk through the center, searching for a café that is still open.

The sense is almost the same as the original. The original sentence treats promenas and serĉas as two parallel actions:

• Ni promenas … kaj serĉas …

With serĉante, serĉi becomes more clearly an action that happens while walking. Both styles are correct and idiomatic.