"They eat an orange."
Translation:Ellos comen una naranja.
Why is ustedes wrong in this situation, is it not the plural of you, so they?
Vosotros/as is the familiar way of you (as a group), whereas the formal way is ustedes. Always have in mind usted/es always conjugates in 3rd person.
You could translate it into "Ellos comen una naranja" or "Ellas comen una naranja", both are correct.
Do you need to say 'ellos' in this sentance?
Could you just say 'comen una naranja'? If not why? And does this work with all verbs, where the pronoun is just extra?
It should be una naranja unless you want to justify 1 orange or many oranges.
Because nosotros is for a group of people, ellos or ellas is referring to them as the third person. Ustedes is you as if im talking to you directly
I get the basic format, but why when I say the above translation correctly it comes up as the correct translation is this: "ellos comen una china" ?