Learn Hardcore Esperanto: Post la arbaro ni revenas en la centron kaj trinkas teon en trankvila kafejo vespere. - After the forest we return to the center and drink tea in a quiet café in the evening.

Esperanto often leaves out the “implied activity”, so post la arbaro can stand for something like post la promenado en la arbaro (after the walk in the forest).

If you clearly wanted the spatial meaning “behind the forest”, you’d usually give more context, e.g.:

Post la arbaro estas lago. – Behind the forest there is a lake.

What’s the difference between post and malantaŭ? Could we say malantaŭ la arbaro instead?

post = after (in time) or behind (in space)
malantaŭ = only behind (in space), never temporal

So:

Post la milito – After the war ✔
Malantaŭ la milito – nonsense ✖

Spatially, post la arbaro and malantaŭ la arbaro can both mean behind the forest, but malantaŭ is unambiguously spatial, while post can still be read as temporal without context.

In your sentence, you can’t replace it with malantaŭ, because you want a time meaning (“after the forest visit”), not a place “behind the forest”.

Why is it en la centron with -n, instead of en la centro?

With en, the -n on the noun shows movement toward a place:

en la centro – in the center (location, static)
en la centron – into / to the center (direction, movement)

So:

Ni estas en la centro. – We are in the center.
Ni revenas en la centron. – We return to / into the center.

Your sentence describes going back into the center, so en la centron is correct.

Could we say revenas al la centro instead of revenas en la centron? Is there a difference?

Yes, both are possible:

reveni al la centro – return to the center
reveni en la centron – return into the center

Nuance:

al focuses on the destination as a point (“to the center”).
en
- -n focuses on entering into that place.

In practice, for a city center, both mean almost the same in this context. Many speakers might even find reveni al la centro slightly more common-sounding, but reveni en la centron is fully correct.

Why is it teon and not just teo in trinkas teon?

The -n marks the direct object (accusative) of the verb.

teo – tea (basic form)
teon – tea as a direct object (something you drink)

trinki (to drink) normally takes a direct object:

Mi trinkas teon. – I drink tea.
Li trinkis akvon. – He drank water.

Without -n, teo would look like a subject or a predicate noun, which would be wrong here.

Why is there no -n in en trankvila kafejo? Shouldn’t it be en trankvilan kafejon?

Again, -n with en only appears when you show movement into a place:

Ni sidas en trankvila kafejo. – We sit in a quiet café. (location, no -n)
Ni eniras trankvilan kafejon. – We enter a quiet café. (movement, -n)

In your sentence, the café is just the place where we drink:

…kaj trinkas teon en trankvila kafejo…

We’re not describing going into the café, only being in it while drinking. So no -n: en trankvila kafejo.

What does vespere mean, and how is it different from en la vespero?

vespere is an adverb built from vesper- (evening) + -e (adverb ending). It means in the evening / of an evening:

Ni promenas vespere. – We take walks in the evening.

en la vespero is a full phrase with en + noun:

Ni promenas en la vespero.

Differences:

vespere is shorter and very typical, especially for general or habitual time:
- Printempe, somere, aŭtune, vespere…
en la vespero can sound a bit more concrete or “one specific evening” in some contexts.

In your sentence, vespere is the most natural form:

…trinkas teon en trankvila kafejo vespere. – we drink tea in a quiet café in the evening.

Where can vespere go in the sentence? Is the word order fixed?

Esperanto word order is quite flexible. All these are possible and natural:

Post la arbaro ni revenas en la centron kaj vespere trinkas teon en trankvila kafejo.
Post la arbaro, vespere, ni revenas en la centron kaj trinkas teon en trankvila kafejo.
Post la arbaro ni revenas en la centron kaj trinkas teon en trankvila kafejo vespere.

Placing vespere at the end (as in your sentence) is very common for time expressions, but moving it earlier for emphasis or style is fine.

Why is ni not repeated before trinkas? Should it be ni revenas… kaj ni trinkas…?

In Esperanto, as in English, you don’t need to repeat the subject when two verbs share the same one:

Ni revenas en la centron kaj trinkas teon.
– We return to the center and drink tea.

It’s similar to English “We return to the center and drink tea” (you don’t say “and we drink tea” unless for emphasis).

You can repeat ni:

Ni revenas en la centron kaj ni trinkas teon…

but it usually just adds emphasis or a slightly heavier rhythm; it’s not required.

The verbs are in the present tense (revenas, trinkas), but the English might be future (“we will return and drink”). Is that okay?

Yes. Esperanto present tense (-as) can be used for:

Actual present:
- Ni nun revenas en la centron. – We are now returning.
Narration / “vivid” present about a sequence (common in descriptions):
- First we do this, then we do that…
- Post la arbaro ni revenas en la centron kaj trinkas teon…
Planned / scheduled future in informal style, similar to English:
- Tomorrow we go to Paris.
- Morgaŭ ni iras al Parizo.

If you want it clearly future, you can use -os:

Post la arbaro ni revenos en la centron kaj trinkos teon…

What does kafejo literally mean? Why not kafeo?

Esperanto uses the suffix -ej- to mean “place where X happens / exists”.

kaf- – coffee
kafejo – a place related to coffee → café, coffeehouse

Compare:

lerni → lernejo – school (place where one learns)
legi → legejo – reading room / place where one reads

kafeo would just mean “some kind of thing called kafeo”, not “café”. The standard word for “café” is kafejo.

Why is it trankvila kafejo and not kafejo trankvila? Where do adjectives go?

Adjectives in Esperanto can go before or after the noun they describe:

trankvila kafejo
kafejo trankvila

Both mean quiet café. The most common, neutral order is adjective + noun:

granda domo, bela urbo, trankvila kafejo

Putting the adjective after can sound a bit more poetic, emphatic, or stylistic:

Ni sidas en kafejo trankvila kaj komforta.

Whichever order you choose, the adjective always agrees in number and case with its noun (here: singular, no -n, so trankvila kafejo).