Learn Hardcore Croatian: U slobodno vrijeme oni gledaju u nebo i maštaju o svemiru. - In their free time they look at the sky and daydream about space.

Accusative for direction / time span: u ponedjeljak (on Monday), u nedjelju (on Sunday), u slobodno vrijeme (in free time).
Locative for location / place: u gradu (in the city), u školi (at school).

Here it’s a time expression, so the phrase is in the accusative: u slobodno vrijeme = during free time.

Could you also say “u slobodnom vremenu” instead of “u slobodno vrijeme”?

You can say “u slobodnom vremenu”, and it’s grammatically correct (locative: slobodnom vremenu), but:

“u slobodno vrijeme” is the standard, idiomatic, everyday phrase meaning in (one’s) free time.
“u slobodnom vremenu” sounds more formal, bookish, or slightly awkward in most everyday contexts.

If you’re talking about a general habit, as in this sentence, always prefer:

✅ U slobodno vrijeme čitam. – In my free time, I read.

Reserve “u slobodnom vremenu” for rare, more abstract or stylistically marked contexts; most learners can safely ignore it and just use “u slobodno vrijeme”.

Why is the pronoun “oni” used here? Could you leave it out?

In Croatian, subject pronouns (ja, ti, on, ona, ono, mi, vi, oni) are usually dropped, because the verb ending already tells you the person and number.

gledaju (3rd person plural) already shows “they”.

So both are correct:

U slobodno vrijeme oni gledaju u nebo i maštaju o svemiru.
U slobodno vrijeme gledaju u nebo i maštaju o svemiru.

Including “oni”:

adds a bit of emphasis on they (as opposed to someone else),
or can help clarity in a longer context with several possible subjects.

For neutral, context‑internal sentences, dropping “oni” is very natural.

Why is the present tense used for something that seems like a habit, not something happening just now?

Croatian present tense (gledaju, maštaju) covers both:

Right now actions
- Sada gledaju u nebo. – Right now they are looking at the sky.
Habitual / repeated actions (what they usually do)
- U slobodno vrijeme gledaju u nebo. – In their free time they look at the sky.
  (= they habitually do this when they have free time)

There is no separate “present continuous” form like English are looking / are dreaming. Context (time expressions like u slobodno vrijeme, svake večeri, vikendom) tells you it’s a habit.

Why is it “gledaju u nebo” and not just “gledaju nebo”?

Both forms exist, but their nuance differs.

gledati (ACC) = to watch / look at something as an object:
- gledaju nebo – they are watching the sky (similar to observe the sky as an object of study, like astronomers).
gledati u (ACC) = to look towards / into something, focusing on the direction of gaze:
- gledaju u nebo – they are looking up at the sky.
  The preposition u highlights the direction: their eyes are turned into/up at the sky.

In this sentence, “gledaju u nebo” is more natural, because it’s about the act of gazing upwards, not scientifically observing the sky.

Why is it “u nebo” and not “u nebu”?

The preposition u can take accusative or locative:

u + accusative = motion / direction into, to:
- idem u školu – I’m going to school
- gledaju u nebo – they are looking into / toward the sky (their gaze is directed there)
u + locative = location in, inside:
- u školi – in/at school
- u nebu – in the sky (something is located inside the sky)

Even though no physical movement happens, verbs of looking / staring often behave like verbs of direction, so they commonly use:

gledati u (ACC): u nebo, u pod, u zid
gledati u nebu would mean in the sky as a location, and sounds off in this context.

What case is “svemiru” in “maštaju o svemiru”, and why is it used?

“svemiru” is locative singular of svemir (universe, outer space).

Nominative: svemir
Locative (sing.): svemiru

The preposition o (“about”) in Croatian always takes the locative case:

o čemu? – about what?
o svemiru – about the universe / about space
o školi, o poslu, o tebi – about school, about work, about you

So:

✅ maštaju o svemiru – they dream/fantasize about the universe
❌ maštaju o svemir – wrong (wrong case)

What is the nuance of “maštati”? Is it the same as “dream”?

Maštati means:

to fantasize, to daydream, to imagine things, often unreal or idealized.

It’s close to:

sanjariti – to daydream, be dreamy
and to English “to fantasize / to daydream”.

It’s not about sleeping dreams (for that, you use san “dream” and sanjati “to dream”):

Sanjam čudne snove. – I dream strange dreams (at night).
Maštam o putovanju u svemir. – I fantasize about traveling to space.

So in “maštaju o svemiru”, they are fantasizing, daydreaming about the universe, not literally having dreams while sleeping.

Can the word order be changed, e.g. “Oni u slobodno vrijeme gledaju u nebo…”?

Yes. Croatian word order is quite flexible, and many permutations are grammatically valid. All of these are possible:

U slobodno vrijeme oni gledaju u nebo i maštaju o svemiru.
U slobodno vrijeme gledaju u nebo i maštaju o svemiru.
Oni u slobodno vrijeme gledaju u nebo i maštaju o svemiru.
Oni gledaju u nebo i maštaju o svemiru u slobodno vrijeme. (less neutral, heavier at the end)

Changes in order mainly affect:

emphasis (what you highlight)
information structure (what’s new vs. known)

The most neutral, typical patterns for this sentence are:

U slobodno vrijeme gledaju u nebo i maštaju o svemiru.
U slobodno vrijeme oni gledaju u nebo i maštaju o svemiru. (with a bit more emphasis on oni)

Why is there no comma before “i maštaju”?

In Croatian, you do not put a comma between two verbs that share the same subject and form a compound predicate:

Oni gledaju u nebo i maštaju o svemiru.
- one subject (oni)
- two verbs (gledaju, maštaju)
- no comma: gledaju u nebo i maštaju…

You would use a comma with different subjects or in more complex structures, for example:

Oni gledaju u nebo, a djeca se igraju. – They look at the sky, and the children are playing.

Here, because oni is the subject of both gledaju and maštaju, no comma is needed.