Slon je bio veći nego što smo očekivali, dok je majmun bio brži i nemirniji.

Je bio is the masculine singular past tense of biti (to be).

• je = is/has as an auxiliary here
• bio = past active participle, masculine singular

So:

• Slon je bio veći = The elephant was bigger
• majmun je bio brži i nemirniji = the monkey was faster and more restless

Croatian often repeats the verb in each clause when English might also repeat was. It keeps the sentence clear and balanced.

They agree with the nouns they describe:

• slon = masculine singular
• majmun = masculine singular

So the comparative adjectives are also masculine singular:

• veći = bigger
• brži = faster
• nemirniji = more restless

If the noun were feminine, the form would change:

• slonica je bila veća = the female elephant was bigger

If it were neuter:

• dijete je bilo brže = the child was faster

Croatian comparatives are often formed in different ways depending on the adjective.

In this sentence:

• velik → veći = big → bigger
• brz → brži = fast → faster
• nemiran → nemirniji = restless → more restless

A few things to notice:

1. Some adjectives change their stem:

   • velik does not become velikiji
   • it becomes veći

2. Some take -ji:

   • brz → brži

3. Longer adjectives often take -iji:

   • nemiran → nemirniji

So, unlike English, you cannot always predict the comparative mechanically. Many are regular, but some need to be learned individually.

Here nego što means than in the sense of than we expected.

So:

• veći nego što smo očekivali = bigger than we expected

This structure is very common when what comes after than is a whole clause, not just a noun.

Compare:

• veći od majmuna = bigger than the monkey
• veći nego što smo očekivali = bigger than we expected

A useful rule:

• od is commonly used before a noun/pronoun
• nego (što) is used before a clause or verbal idea

In standard Croatian, nego što smo očekivali is the normal and safest form here.

The što introduces the subordinate clause:

• nego što smo očekivali = than what we expected / than we had expected

In everyday speech, you may sometimes hear shortened versions, but for learners, nego što is the best pattern to remember when a full clause follows.

Croatian often leaves out subject pronouns when they are already clear from the verb form.

• smo očekivali already tells you the subject is we
• mi smo očekivali would also be correct, but mi is usually added for emphasis or contrast

So:

• smo očekivali = we expected
• mi smo očekivali = we expected (with extra emphasis on we)

This is normal in Croatian, because verb endings often show who is doing the action.

Because the subject is we.

The verb phrase is:

• smo očekivali

This is the past tense for we expected.

Breakdown:

• smo = auxiliary for we
• očekivali = past participle, masculine plural/mixed plural form

Croatian past tense agrees with the subject in gender and number:

• ja sam očekivao / očekivala = I expected
• mi smo očekivali / očekivale = we expected

The form očekivali is the usual masculine plural or mixed-gender plural form.

Here dok means while or whereas.

It connects two contrasting ideas:

• The elephant was bigger than we expected
• while / whereas the monkey was faster and more restless

So in this sentence, dok is not mainly about two actions happening at the same time. It is more about contrast between the elephant and the monkey.

You can think of it here as:

• while
• whereas
• but by contrast

Croatian has no articles like English a and the.

So:

• slon can mean an elephant or the elephant
• majmun can mean a monkey or the monkey

The exact meaning depends on context.

In your sentence, the context makes them definite in English, so we translate them as the elephant and the monkey.

This is a very common adjustment English speakers have to make when learning Croatian.

That word order is the normal, natural order for this kind of clause.

• nego što introduces the comparison
• smo očekivali = we expected

Croatian word order is more flexible than English, but not random. This version sounds neutral and standard.

You could change word order in Croatian for emphasis in some contexts, but learners should first master the basic pattern:

• comparative + nego što + clause

Example:

• bolji nego što sam mislio = better than I thought
• teži nego što izgleda = heavier than it looks

Not in the same way.

You use od when comparing with a noun or pronoun:

• Slon je veći od majmuna. = The elephant is bigger than the monkey.

But in your sentence, the comparison is with a whole idea:

• than we expected

So Croatian uses:

• veći nego što smo očekivali

That is why od would not fit naturally here.

Croatian usually prefers a comparative adjective form when one exists.

So:

• nemiran = restless
• nemirniji = more restless

This is more natural than trying to build it analytically.

English often uses both patterns:

• faster
• more restless

Croatian also has some analytic comparison in certain cases, but with common adjectives like nemiran, the built comparative nemirniji is the normal choice.

It is neutral, standard Croatian.

Nothing in it is slangy or unusually formal. It would sound natural in writing or speech.

Useful features of standard Croatian in this sentence include:

• nego što for clause comparison
• dok for contrast
• normal comparative adjective forms like veći, brži, nemirniji

So this is a good model sentence for learners.