Moja sestra stavlja breskve u malu vrećicu, a ja nosim drugu vrećicu za kruh.

Because moja sestra is the subject of the sentence, so it is in the nominative case.

• moja sestra = my sister as the person doing the action
• moju sestru would be accusative, used when my sister is the direct object

Compare:

• Moja sestra stavlja... = My sister is putting...
• Vidim moju sestru. = I see my sister.

So here moja and sestra are both nominative singular feminine.

Because the sentence is talking about peaches in the plural, not a peach in the singular.

• breskva = peach
• breskve = peaches

In this sentence, breskve is also the direct object of stavlja, so it is in the accusative plural. For this noun, the accusative plural looks the same as the nominative plural.

So:

• breskva = one peach
• breskve = peaches

Because u here expresses movement into something, and that requires the accusative case.

The basic noun is:

• vrećica = bag

But after u meaning into, it becomes:

• u vrećicu = into a bag

The adjective must agree with the noun, so:

• mala vrećica = a small bag
• u malu vrećicu = into a small bag

Both malu and vrećicu are feminine singular accusative.

This is a very important Croatian pattern:

• u + accusative = movement into
• u + locative = location inside

So:

• stavlja breskve u malu vrećicu = she is putting the peaches into the small bag
• breskve su u maloj vrećici = the peaches are in the small bag

So the sentence uses u malu vrećicu because the action is directional: the peaches are going into the bag.

drugu is the feminine singular accusative form of drugi.

In this sentence, drugu vrećicu means:

• another bag
• or sometimes the second bag, depending on context

Because vrećicu is feminine singular accusative, the adjective must match it:

• druga vrećica = another/second bag
• nosim drugu vrećicu = I am carrying another/second bag

So drugu changes its ending to agree with vrećicu.

Because za here takes the accusative case, and kruh is a masculine inanimate noun whose accusative singular is the same as its nominative singular.

So:

• kruh = bread
• za kruh = for bread

Even though the case changes grammatically, the form does not change here.

This is very common with masculine inanimate nouns in Croatian.

Here za kruh means for bread, in the sense of intended for bread or used for bread.

So:

• vrećica za kruh = a bag for bread

This use of za often expresses purpose or intended use.

Other examples:

• čaša za vodu = a glass for water
• kutija za cipele = a box for shoes

So drugu vrećicu za kruh means another bag for bread.

A often connects two clauses with a slight contrast, switch of topic, or comparison.

In this sentence:

• Moja sestra stavlja... = my sister is doing one thing
• a ja nosim... = and I am doing something else

So a is very natural here because it feels like:

• while I...
• and I, on the other hand...
• whereas I...

It is not as strong as ali (but), and it is more contrastive than plain i (and).

Yes, Croatian often leaves out subject pronouns because the verb ending already shows the person.

So nosim already means I carry / I am carrying.

But ja is included here for emphasis or contrast:

• a ja nosim... = and I am carrying...

This makes the contrast with moja sestra clearer.

Without ja, the sentence would still be grammatical:

• Moja sestra stavlja breskve u malu vrećicu, a nosim drugu vrećicu za kruh.

But that version sounds less balanced and less explicit. With ja, the contrast is stronger and more natural.

Both are in the present tense.

• stavlja = she puts / she is putting
• nosim = I carry / I am carrying

Croatian present tense can often correspond to both:

• a simple present in English
• a present continuous in English

So depending on context:

• stavlja can mean puts or is putting
• nosim can mean carry or am carrying

In this sentence, the natural English meaning is probably the continuous one: is putting and am carrying.

Because stavlja is from the imperfective verb stavljati, which is used for an ongoing, repeated, or uncompleted action.

• stavljati → stavlja
• staviti → stavi

Very roughly:

• stavlja = is putting / puts
• stavi = puts once / will put / let him put, depending on context

In a sentence describing what is happening as part of a scene, stavlja is the natural choice.

Yes. drugi can mean either:

• another / a different
• second

The exact meaning depends on context.

So:

• nosim drugu vrećicu za kruh could mean
  I’m carrying another bag for bread
• or
  I’m carrying the second bag for bread

If the wider situation is not given, both are possible.

No. Standard Croatian does not have articles like English the and a/an.

So words like:

• sestra
• breskve
• vrećica
• kruh

can mean a sister, the sister, peaches, the peaches, and so on depending on context.

Croatian usually expresses definiteness through:

• context
• word order
• emphasis
• demonstratives such as taj, ovaj, onaj when needed

So the absence of articles in this sentence is completely normal.

Not completely. Croatian word order is more flexible than English because case endings show grammatical roles.

The given sentence is very natural and neutral:

• Moja sestra stavlja breskve u malu vrećicu, a ja nosim drugu vrećicu za kruh.

But other orders are possible for emphasis, for example:

• Breskve moja sestra stavlja u malu vrećicu...
• Ja nosim drugu vrećicu za kruh...

However, those versions change the focus or sound marked. The original order is the most straightforward for a learner.

In vrećicu, the letter ć is a soft sound, somewhat like a very soft ch/t sound. English does not have an exact match.

A rough guide:

• vre-ći-cu

The ć is softer than č.

Also:

• vrećicu has stress typically near the beginning in careful pronunciation, though stress details are often not the first thing learners need to master
• kruh ends with a clearly pronounced h, unlike English silent letters

The most useful thing for a beginner is to notice that ć and č are different sounds in Croatian, even if they may sound similar at first.