"They are going to wait for me."
Translation:Ellas me van a esperar.
from the spanish.about.com link:
Uses for por:
Denoting a time or duration when something occurs. Viajamos por tres semanas. We're traveling for three weeks.
Uses for para:
Meaning by or for when referring to a specific time: Necesito el regalo para mañana. I need the gift for tomorrow. Vamos a la casa de mi madre para el fin de semana. We're going to my mother's for the weekend.
that's going to take some "time" before i understand.
I know this question is 3 years old, but I feel it needs to be addressed.
You are asking if the future tense (conjugated from the infinitive verb) could be substituted for the phrasal future tense (ir + a + infinitive verb).
In real life, they mean about the same, but not exactly, and I'm sure no one would care or notice if you substituted one for the other. In this case, "esperaremos" would mean "we will wait" and "esperarán" would mean "they will wait". Whereas, "vamos a esperar" would literally mean "we are going to wait" and "van a esperar" sould mean "they are going to wait". So, there is a bit of difference in the literal translation, and they can have a nuance of difference, but I believe it is mostly about preference in the moment.
Regardless of which you use in real life, the whole point of this lesson is to learn the phrasal future form of conjugation. If you answer with something different, then you are not learning what Duolingo is trying to teach you. They are looking for the verb phrase structured as "ir + a + infinitive verb".
Sentence to translate - 'they are going to wait for me'
Multiple choice selection One says 'ellas me van a esperar' One says 'ellos me van a esperar'
I picked the masculine version and was dinged because the correct answer was the feminine version. No context was given to determine the gender...