Learn Hardcore Croatian: Jedan putnik je ljut, jer misli da je izlet predug. - One passenger is angry because he thinks the trip is too long.

Jedan putnik je ljut ≈ “One (particular) passenger is angry” / “A passenger is angry.”
Putnik je ljut is also grammatical, but it usually sounds more like “The passenger is angry” (a specific passenger you both already know about).

So jedan helps show that we are introducing some passenger, not talking about “the known passenger.”

Why is there a comma before jer?

In Croatian, you normally put a comma before jer when it introduces a clause meaning because.

…je ljut, jer misli… = “…is angry, because he thinks…”

This is different from English, where you often don’t put a comma before because. In Croatian, the comma is standard: jer starts a new clause explaining the reason.

What’s the function of jer here, and could we use zato što instead?

Jer is a conjunction meaning because. It introduces the reason for being angry.

Jedan putnik je ljut, jer misli da je izlet predug.
“A passenger is angry because he thinks the excursion is too long.”

You can often replace jer with zato što:

Jedan putnik je ljut, zato što misli da je izlet predug.

Both are correct. Roughly:

jer = plain “because,” very common and neutral.
zato što = “because,” a bit more explicit/emphatic (“for the reason that…”).

In everyday speech they’re both very frequent, and here they mean the same.

Why is ljut used, and how does it agree with putnik?

Ljut is an adjective meaning angry. In Croatian, adjectives must agree with the noun in:

gender
number
case

Putnik is masculine, singular, nominative. So ljut must also be:

masculine singular nominative: ljut

If the passenger were female (putnica), the sentence would change to:

Jedna putnica je ljuta, jer misli da je izlet predug.

Note jedna (feminine) and ljuta (feminine) now agree with putnica (feminine).

Why is the verb je used twice in the sentence?

There are actually two different “is” relations here:

Jedan putnik je ljut – “One passenger is angry.”
- je is the 3rd person singular of biti (to be), linking putnik and ljut.
…jer misli da je izlet predug. – “because he thinks that the trip is too long.”
- This je links izlet and predug inside the subordinate clause introduced by da.

So you need je in both places—each je belongs to a different clause.

What does misli da je… literally mean, and why do we need da?

Misli is he/she thinks, from misliti.
Da is a conjunction often translated as that in this kind of sentence.

So misli da je izlet predug literally is:

“(he) thinks that the trip is too long.”

You normally can’t drop da here.
✗ misli je izlet predug is ungrammatical.

In Croatian, after verbs of thinking, saying, believing, etc., you almost always introduce the following clause with da:

Vjeruje da je u pravu. – “He believes (that) he is right.”
Kaže da nema vremena. – “She says (that) she has no time.”
Misli da je izlet predug. – “He thinks (that) the trip is too long.”

Why is the word order da je izlet predug and not da izlet je predug?

In Croatian, finite verbs prefer to be in the “second position” in a clause (after the first stressed element). After da, the first stressed word is usually the verb or the subject, and several orders are possible, but some sound more natural.

The most neutral here is:

da je izlet predug (that is the trip too-long)

You could say:

da je predug izlet – this is also correct, but puts a bit more focus on predug (“that too long is the trip” / “that it is too long, the trip”).

✗ da izlet je predug sounds wrong; the verb normally doesn’t go at the end like that in this kind of clause.

What’s the difference between dug and predug?

dug = long
predug = too long (the prefix pre- adds the meaning “too / overly / excessively”)

Examples:

Izlet je dug. – “The trip is long.” (neutral description)
Izlet je predug. – “The trip is too long.” (it’s longer than it should be)

Other examples with pre-:

skup – expensive → preskup – too expensive
mali – small → premali – too small

Which case are putnik and izlet in, and why?

Both putnik and izlet are in nominative singular:

Jedan putnik je ljut… – putnik is the subject of je (ljut).
…da je izlet predug. – izlet is the subject of je (predug) in the subordinate clause.

In Croatian, the subject of a normal “X is Y” sentence is in the nominative:

Izlet je kratak. – “The trip is short.”
Putnik je umoran. – “The passenger is tired.”

Could we drop je and say Jedan putnik ljut like in English “one passenger angry”?

No, not in standard Croatian. You need the verb biti (je) to form the “X is Y” structure:

Jedan putnik je ljut. – correct
✗ Jedan putnik ljut. – incomplete / ungrammatical as a normal sentence

You might see “Putnik ljut, vodič zbunjen.” in headlines, notes, or poetic/telegraphic style—that’s a deliberate omission for style or brevity, not normal full-sentence grammar.

Why is misli in the present tense, not past, if the anger already exists?

Croatian uses the present tense here just like English:

(On) je ljut, jer misli da je izlet predug.
“He is angry because he thinks the trip is too long.”

Both anger and thinking are viewed as true now, so present tense is natural.

If you wanted to talk about something in the past, you’d change the verbs:

Jedan putnik je bio ljut, jer je mislio da je izlet predug.
“One passenger was angry because he thought the trip was too long.”

How would the sentence change if the passenger were female or if there were several passengers?

For one female passenger:

Jedna putnica je ljuta, jer misli da je izlet predug.
- jedna (feminine)
- putnica (female passenger)
- ljuta (feminine form of ljut)

For several passengers:

Neki putnici su ljuti, jer misle da je izlet predug. – “Some passengers are angry because they think the trip is too long.”
- neki putnici – “some passengers” (plural)
- su ljuti – “are angry” (plural verb + plural adjective)
- misle – “they think” (3rd person plural)

You must adjust determiners, nouns, verbs, and adjectives to match gender and number.