Majmun je sjeo na granu i uzeo bananu iz ruke moje sestre.

This is the normal Croatian past tense, often called the perfect. It is formed with:

• the auxiliary biti in the present tense: je
• plus a past participle: sjeo, uzeo

So:

• je sjeo = sat down
• (je) uzeo = took

In everyday Croatian, this is the standard way to talk about completed past actions.

Because the past participle agrees with the subject in gender and number.

Here the subject is majmun, which is masculine singular, so the forms are:

• sjeo
• uzeo

If the subject were feminine singular, you would get:

• sjela
• uzela

If it were plural, the endings would change again.

Croatian clitics, including je, usually go in the second position in the clause.

So the neutral order is:

• Majmun je sjeo ...

not normally:

• Je majmun sjeo ...

This second-position rule is very common in Croatian and is something English speakers often have to get used to.

Because both verbs share the same subject and the same tense, Croatian often uses the auxiliary only once:

• Majmun je sjeo na granu i uzeo bananu ...

This is completely normal. You could repeat the auxiliary in some contexts, but it is usually omitted here because it would sound unnecessary.

Because sjeo and uzeo are perfective forms, and they describe completed, one-time actions.

• sjesti / sjeo = to sit down / sat down
• uzeti / uzeo = to take / took

These fit the sentence because the monkey:

1. sat down on the branch
2. took the banana

If you used imperfective forms such as uzimao, it would suggest an ongoing, repeated, or uncompleted action. Also, sjedio means was sitting / sat (in a state of being seated), not the moment of sitting down.

Because na can take different cases depending on meaning:

• na + accusative = movement onto something
• na + locative = being on something

Here the monkey is moving to the branch, so Croatian uses the accusative:

• na granu = onto the branch

If you said na grani, that would mean on the branch as a location, not the motion toward it.

Because both are feminine singular nouns that are in the accusative singular.

Their dictionary forms are:

• grana
• banana

In the accusative singular, feminine nouns ending in -a usually change to -u:

• grana → granu
• banana → bananu

But notice the reason for the accusative is different in each case:

• na granu: accusative because of movement with na
• bananu: accusative because it is the direct object of uzeo

After iz, Croatian uses the genitive.

So:

• ruka → ruke
• moja sestra → moje sestre

That gives:

• iz ruke moje sestre = from my sister's hand

This part shows two useful patterns:

1. iz + genitive
2. possession is often expressed with the genitive, where English would use 's

So moje sestre literally means of my sister.

Because iz requires the genitive, and the genitive singular of ruka is ruke.

If it were plural, the genitive plural would be:

• ruku

So:

• iz ruke = from the hand
• iz ruku = from the hands

That is why this sentence clearly means one hand.

Yes, Croatian word order is more flexible than English, but not all versions sound equally neutral.

This sentence is natural because:

• it presents the actions in sequence
• it keeps the clitic je in its usual second position

Other word orders are possible for emphasis, but Majmun je sjeo na granu i uzeo bananu iz ruke moje sestre. is a very normal, neutral version.

Yes. In this sentence, moje sestre functions like English my sister's.

Croatian often uses a noun in the genitive instead of an English-style apostrophe construction:

• ruka moje sestre = my sister's hand
• literally: the hand of my sister

So English possession with 's is often expressed in Croatian with the genitive case.