Sutra ću čistiti pod u hodniku, jer danas nemam vremena.

This is Future I in Serbian.

It is usually formed with:

• a short form of hteti = ću, ćeš, će, ćemo, ćete, će
• plus the infinitive

So:

• ću čistiti = I will clean

Other examples:

• ću raditi = I will work
• ćeš doći = you will come
• će kupiti = he/she will buy

In this sentence, čistiti is the infinitive to clean.

Because ću is a clitic, and clitics in Serbian usually go in the second position in the clause.

So:

• Sutra ću čistiti... is natural
• the first element is Sutra
• the clitic ću comes right after it

You can also say:

• Ja ću sutra čistiti pod u hodniku.

But Sutra čistiću... is not the normal pattern here.

Because Serbian often drops subject pronouns when the meaning is already clear from the verb form.

Here, both:

• ću
• nemam

already show first person singular, so ja is unnecessary.

Serbian often prefers:

• Sutra ću čistiti... instead of
• Ja ću sutra čistiti...

You would add ja mainly for emphasis or contrast:

• Ja nemam vremena, ali on ima.

This is a question of aspect, which is very important in Serbian.

• čistiti = imperfective
• očistiti = perfective

Very roughly:

• čistiti focuses on the activity/process of cleaning
• očistiti focuses on finishing the cleaning, getting the result

So:

• Sutra ću čistiti pod = Tomorrow I’ll be cleaning / I’ll clean the floor
• Sutra ću očistiti pod = Tomorrow I’ll clean the floor completely / get it done

In many contexts, both are possible, but they give slightly different emphasis.

Pod is the direct object of čistiti, so it is in the accusative case.

However, pod is:

• masculine
• inanimate
• singular

For many masculine inanimate nouns in Serbian, the accusative singular is the same as the nominative singular.

So:

• nominative: pod
• accusative: pod

That is why the form does not change.

Because u can take different cases depending on the meaning:

• u + locative = location, in
• u + accusative = movement toward/into, into

Here the meaning is location:

• u hodniku = in the hallway

If you were talking about movement, you would use:

• u hodnik = into the hallway

Compare:

• Čistim pod u hodniku. = I am cleaning the floor in the hallway.
• Ulazim u hodnik. = I am entering the hallway.

There is no separate word for the because Serbian does not have articles like English a/an/the.

So:

• pod can mean floor or the floor
• hodniku can mean hallway or the hallway

The exact meaning comes from context.

In this sentence, English naturally translates it with the:

• the floor
• the hallway

Nemam vremena is the normal Serbian way to say I don’t have time in the sense of I don’t have enough/any time available.

Here vremena is genitive singular.

This is a very common expression:

• imam vremena = I have time
• nemam vremena = I don’t have time

The genitive here suggests an indefinite amount of time, which is why it sounds natural in Serbian.

So for learners, it is best to memorize:

• imati vremena
• nemati vremena

as a set phrase.

Jer means because.

Yes, you could also use zato što, and the meaning would stay very similar.

Compare:

• ..., jer danas nemam vremena.
• ..., zato što danas nemam vremena.

Both mean:

• ..., because today I don’t have time.

Jer is short and very common.
Zato što is also very common and can sound a little more explicit.

Because jer introduces a subordinate clause, and in Serbian this clause is normally separated by a comma.

So:

• Sutra ću čistiti pod u hodniku, jer danas nemam vremena.

That comma is standard punctuation.

Yes. Serbian word order is fairly flexible, and changing it often changes emphasis, not the basic meaning.

Possible versions include:

• Sutra ću čistiti pod u hodniku.
• Ja ću sutra čistiti pod u hodniku.
• Pod u hodniku ću čistiti sutra.

But there is one important rule: clitics like ću usually stay in second position in their clause.

So when you move words around, you must still place ću correctly.

Yes, sometimes Serbian uses the present tense for a planned future action, especially in everyday speech.

For example:

• Sutra čistim pod u hodniku.

This can also mean:

• Tomorrow I’m cleaning the floor in the hallway.

That said, Sutra ću čistiti... is a very clear and standard future form, so it is an excellent sentence for learning.