"¿Qué están comiendo?"
Translation:What are they eating?
"What are you all eating?" not accepted as of 2016-01-12, Ustedes can be translated as you all in English and I believe helps clarify that you are speaking to a group. Should be accepted.
That's a feature of You (Singular) You (Plural). Saying "You all" is extra. Some might even say "Ya'll"
yes. estar (conjugated) + present participle = what some one is doing know estoy estudiando = I am studying,
I guess I don't get why "gerundio" is translated as "gerund." It is translated the same way in my Spanish dictionaries and Spanish grammar books, so there is clearly consensus on this. But--a gerund in English is a verbal noun and nothing else. Participles and past participles do not overlap with gerunds in English. You must know more than I!
In English, the gerund looks like the present participle. (I like running.)
In Spanish, the gerund looks like the verbal infinitive. (Me gusta correr.)
However, el gerundio translates as the present participle, which is not actually the same as the English "gerund", though it shares the same construction (-ing/-ando).
It's a point of confusion for many beginning and intermediate learners.