Bušilica i libela su na podu.

Because the subject is bušilica i libela — the drill and the spirit level — which is plural as a whole.

• je = is (3rd person singular)
• su = are (3rd person plural)

So:

• Bušilica je na podu. = The drill is on the floor.
• Bušilica i libela su na podu. = The drill and the spirit level are on the floor.

Because na changes case depending on meaning.

Here, na podu expresses location: something is already on the floor. With location, na takes the locative case.

• pod = floor (dictionary form / nominative)
• na podu = on the floor (locative)

Compare:

• Bušilica je na podu. = The drill is on the floor.
• Stavljam bušilicu na pod. = I am putting the drill onto the floor.

So:

• na + locative = location
• na + accusative = movement onto something

They are in the nominative singular.

That is because they are the two nouns making up the subject of the sentence:

• bušilica = drill
• libela = spirit level

Even though the whole subject is plural because of and, each noun itself is still singular.

So the structure is basically:

• [Bušilica] + [i] + [libela] + [su] + [na podu]
• drill + and + spirit level + are + on the floor

Because Serbian normally has no articles like English a/an and the.

So bušilica can mean:

• a drill
• the drill

And libela can mean:

• a spirit level
• the spirit level

The exact meaning depends on context.

That means Bušilica i libela su na podu could be understood as either:

• A drill and a spirit level are on the floor
• The drill and the spirit level are on the floor

Usually the situation tells you which one is meant.

Yes. Serbian word order is more flexible than English word order.

This sentence can also appear as:

• Na podu su bušilica i libela.

That version puts more focus on where they are: On the floor are the drill and the spirit level / more naturally in English, The drill and the spirit level are on the floor.

The original version:

• Bušilica i libela su na podu

is neutral and very natural.

In Serbian, the auxiliary su is a clitic, which means it tends to appear in an early position in the sentence, often after the first phrase.

Here the first phrase is the compound subject:

• Bušilica i libela

So su comes right after it:

• Bušilica i libela su na podu.

This placement is normal and natural.

Yes, i means and.

In this sentence:

• bušilica i libela = the drill and the spirit level

It joins the two nouns into one compound subject, which is why the verb becomes plural: su.

Both are feminine nouns.

You can often tell because they end in -a, which is a very common feminine ending in Serbian.

• bušilica — feminine
• libela — feminine

This matters when you add adjectives or past-tense forms, because those must agree in gender and number.

For example:

• Nova bušilica je na podu. = The new drill is on the floor.
• Nova libela je na podu. = The new spirit level is on the floor.

If you describe both together, you would use plural agreement.

Libela is a real and understandable word, often used for a spirit level or the leveling tool/component. Depending on region and context, people may also say things like vodena vaga for a spirit level.

So a learner may encounter more than one term in real life. But in this sentence, libela is perfectly fine.

A rough pronunciation guide is:

Boo-shee-LEE-tsa ee lee-BEH-la soo na POH-doo

A few sound notes:

• š sounds like English sh
• č would sound like ch, but it does not appear here
• c in bušilica sounds like ts
• stress can vary by dialect, but the rough guide above is enough for a learner

So:

• Bušilica ≈ boo-shee-LEE-tsa
• libela ≈ lee-BEH-la
• su ≈ soo
• na podu ≈ na POH-doo

Yes, but Serbian usually does not need subject pronouns unless you want emphasis or contrast.

So the normal sentence is simply:

• Bušilica i libela su na podu.

You would not usually add a pronoun like one here, because the subject nouns are already stated.

Serbian commonly leaves pronouns out when they are not needed.

It follows a very straightforward pattern:

• Subject: Bušilica i libela
• Verb: su
• Prepositional phrase: na podu

So literally:

• Drill and spirit-level are on floor

Natural English:

• The drill and the spirit level are on the floor.

This is a very useful pattern to learn:

• X je na Y = X is on Y
• X i Z su na Y = X and Z are on Y

For example:

• Knjiga je na stolu. = The book is on the table.
• Knjiga i olovka su na stolu. = The book and the pencil are on the table.