Večeras pijemo kakao, a sutra ću kupiti još jednu litru vode.

Tonight we’re drinking cocoa, and tomorrow I will buy another liter of water.

Breakdown of Večeras pijemo kakao, a sutra ću kupiti još jednu litru vode.

• piti: to drink
• voda: water
• sutra: tomorrow
• večeras: tonight
• a: and
• htjeti: will
• još: more
• kupiti: to buy
• jedan: one
• kakao: cocoa
• litra: liter

Questions & Answers about Večeras pijemo kakao, a sutra ću kupiti još jednu litru vode.

What does Večeras mean, and is it different from večer or večerom?

Večeras means this evening / tonight (i.e., “on this evening”). It’s an adverb commonly used for “tonight.”

• večer = evening (noun)
• večerom = in the evening (instrumental case), more like “in the evening” in a general sense
  In everyday speech, večeras is the natural choice for “tonight.”

Why is it pijemo and not mi pijemo?

Croatian verb endings already show the subject, so pijemo clearly means we drink / we are drinking.
You can add mi (we) for emphasis or contrast: Mi pijemo kakao, a oni kavu = “We drink cocoa, and they (drink) coffee.”

Does pijemo mean “we drink” (habitually) or “we are drinking” (right now)?

It can mean both, depending on context. With večeras (“tonight”), it strongly suggests a current/near-future situation: Tonight we’re having/drinking cocoa.
Croatian present tense often covers what English expresses with present continuous.

Why is kakao not in a different case? Shouldn’t there be an article like “a” or “the”?

Croatian has no articles (“a/the”), so none appear.
As the direct object of pijemo, kakao is in the accusative, but kakao is typically indeclinable in this use (it often looks the same in nominative/accusative).

What does a mean here, and how is it different from i or ali?

a is a coordinating conjunction meaning roughly and (but with contrast/shift): “... and (then/whereas) ...”

• i = plain and, just adding information
• ali = but, stronger opposition
  Here a nicely signals a switch from “tonight” to “tomorrow.”

How is the future formed in sutra ću kupiti?

This is the common future: ću/ćeš/će + infinitive.

• ću = “I will” (clitic form of htjeti)
• kupiti = infinitive “to buy”
  So (ja) ću kupiti = I will buy. The subject ja is optional.

Why is ću placed after sutra? Can it move?

ću is a clitic and usually takes the second position in the clause (after the first word/phrase).
So: Sutra ću kupiti... is very typical.
You can also say: Ja ću sutra kupiti... (with ja as the first element, then ću in second position).

Why is it kupiti (perfective) and not kupovati?

kupiti is perfective: it focuses on a single completed purchase (“I’ll buy (it)”).
kupovati is imperfective: repeated/ongoing action (“I’ll be buying / I buy regularly”).
With sutra and one specific amount, kupiti is the natural choice.

What does još mean here? Could it also mean “still”?

Yes, još can mean still, but here it means more / another / additional.
još jednu litru vode = one more liter of water / another liter of water.

Why is it još jednu litru and not još jedna litra?

Because it’s the direct object of kupiti (“to buy”), so it goes in the accusative.

• Nominative: jedna litra (one liter)
• Accusative: jednu litru (one liter, as an object)

Why is it litru vode (water in vode), and what case is vode?

vode is genitive singular of voda. After quantities/measure nouns (like litra, kilo, čaša), Croatian commonly uses genitive for the substance:

• litra vode = “a liter of water”
  Similarly: čaša vina (a glass of wine), kilo jabuka (a kilo of apples).

Could I say još jedna litra vode instead, and would it change the meaning?

You could say it, but it would change the grammar/structure.

• Kupit ću još jednu litru vode (accusative object) is the straightforward version.
• Još jedna litra vode is nominative and sounds like a standalone phrase (“Another liter of water!”) or the subject of a sentence, not the object—unless you restructure the sentence.