Ja wolę masło na bułce, a ona dodaje dżem.

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Breakdown of Ja wolę masło na bułce, a ona dodaje dżem.

• ona: she
• na: on
• woleć: to prefer

Questions & Answers about Ja wolę masło na bułce, a ona dodaje dżem.

Do I have to include the pronouns Ja and ona, or can I drop them?

You can drop them. Polish is a pro‑drop language, so the verb endings already show who the subject is. The full version adds emphasis/contrast:

• With pronouns (more contrastive/explicit): Ja wolę masło na bułce, a ona dodaje dżem.
• Without: Wolę masło na bułce, a ona dodaje dżem. If you also drop ona (…, a dodaje dżem), it can sound unclear unless the subject switch is obvious from context.

What does a mean here, and how is it different from i and ale?

• a = and/whereas (mild contrast or comparison of two people/things).
• i = and (just adds information, no contrast).
• ale = but (stronger opposition). Here a is best because we’re contrasting preferences: I prefer butter, whereas she adds jam.

Why is it na bułce and not na bułkę?

Because na takes:

• Locative (answering where?) for position: na bułce = on the roll.
• Accusative (answering onto where?) for movement/direction: na bułkę = onto the roll. Here we’re talking about butter being on the roll, not moving it there.

What case is bułce, and what would the accusative be?