Voda ostavlja trag na posudi.

The sentence breaks down like this:

• voda — the subject of the sentence, in the nominative singular
• ostavlja — the verb, 3rd person singular present
• trag — the direct object, in the accusative singular
• na posudi — a prepositional phrase showing location

So the overall structure is basically:

subject + verb + object + location

Because voda is the nominative singular form, and the subject of the sentence is normally in the nominative.

Here, voda is the thing performing the action, so nominative is the correct case.

A learner often notices vode and wonders about it. That form can mean different things in other contexts, for example:

• genitive singular
• nominative plural
• accusative plural

But in this sentence, the subject is singular, so voda is the right form.

Good question. Trag is the direct object, so it is in the accusative singular.

But with many masculine inanimate nouns in Croatian, the accusative singular looks exactly the same as the nominative singular.

So:

• nominative: trag
• accusative: trag

That is normal.

Compare that with a masculine animate noun, where the accusative usually changes:

• pas = dog, nominative
• psa = dog, accusative

So trag does have the right case here; it just happens to look unchanged.

Because na can take different cases depending on the meaning.

Here it describes a location — the mark is on the container, not moving onto it. With that meaning, na takes the locative.

So:

• na posudi = on the container / on the dish
• na posudu would suggest movement onto the container

A useful rule:

• na + locative = location
• na + accusative = motion toward a surface

Because after na with a location meaning, the noun must be in the locative singular.

The noun posuda is a feminine noun ending in -a, and nouns of that type often form the locative singular in -i:

• posuda → posudi

So the ending -i is showing the required case.

Yes, but it would mean something different.

• na posudi = on the container
• u posudi = in the container

So if the water leaves a mark on the outside or on the surface, na posudi is right.

If you meant that something is inside the container, then u posudi would be the natural choice.

Ostavlja is present tense, 3rd person singular, from the imperfective verb ostavljati.

The imperfective aspect is used for actions that are:

• ongoing
• repeated
• habitual
• general facts

So here it can mean things like:

• water leaves a mark
• water is leaving a mark
• water tends to leave a mark

depending on context.

The perfective partner would be ostaviti, whose 3rd person singular present is ostavi. That form is not the natural choice here if you are stating a general fact.

Yes. Croatian present tense often covers what English separates into:

• simple present: leaves
• present progressive: is leaving

So Voda ostavlja trag na posudi could describe:

• a general truth
• a repeated effect
• something happening right now

The wider context tells you which interpretation is intended.

Croatian word order is fairly flexible because case endings show the grammatical roles.

The version you have:

Voda ostavlja trag na posudi.

is a neutral, natural order.

But other orders are possible for emphasis, for example:

• Na posudi voda ostavlja trag.
  This puts more focus on the location.

• Trag voda ostavlja na posudi.
  This puts more focus on trag.

Even though Croatian allows movement, not every rearrangement sounds equally natural in every context. The original sentence is the safest neutral version.

Croatian normally has no articles.

So a noun like voda, trag, or posuda appears without a separate word for a/an/the.

English forces you to choose:

• water leaves a mark on the container
• the water leaves a mark on the container

Croatian often leaves that distinction to context. The listener figures out whether something is definite or indefinite from the situation, previous mention, or common sense.

The nouns are:

• voda — feminine
• trag — masculine
• posuda — feminine

Gender matters in Croatian because adjectives, pronouns, and some verb forms agree with the noun.

In this sentence, gender is not very visible on the verb ostavlja, because present-tense verb forms do not show gender. But gender would matter elsewhere, especially with adjectives or in the past tense.

For example, if you added an adjective:

• hladna voda = cold water
• jasan trag = a clear mark

The adjective changes to match the noun’s gender.