Breakdown of Oni wyrzucają śmieci dopiero wieczorem.
Questions & Answers about Oni wyrzucają śmieci dopiero wieczorem.
You can absolutely drop oni and say:
- Wyrzucają śmieci dopiero wieczorem.
In Polish, subject pronouns (like ja, ty, on, ona, oni) are often omitted, because the verb ending (-ają) already shows the person and number (here: they).
You typically keep oni when you want to:
- emphasize the subject (they as opposed to someone else):
To nie my, to oni wyrzucają śmieci dopiero wieczorem. – Not us, they take the trash out only in the evening. - make the subject very clear (e.g. when starting a story or in learner materials).
So both are correct; the version without oni is just more neutral and more typical in everyday speech.