I just had this question
Tal vez vosotras ________ cansadas después de bailar.
This was a checkbox question with these options
estuvierais
estuvisteis
estáis
estaréis
estuvieseis
Based on the lesson on this page, I would expect both the indicative and subjunctive to be correct (estuvisteis, estuvierais, estuvieseis).
However, the question had a hint:
(HINT: Conjugate "estar" in El Imperfecto de Subjuntivo)
Based on this I left off the indicative and my responses (just estuvierais and estuvieseis) were scored as correct.
The result is that I'm left uncertain about using estuvisteis here, and about the limits of the applicability of the lesson on the page.
If estuvisteis is OK here, then I think the question should be revised to not have that hint, and to check for the three correct answers. That way students like me wouldn't be confused thinking "Well, in the lesson , it says you can use indicative or subjunctive with no change in meaning. But here, apparently the indicative is wrong, so that lesson can't be trusted. I wonder what the real pattern is. I guess I'll need to look elsewhere to find out."
On the other hand, if the indicative is wrong here, then I think this lesson, or some other lesson, should give some hint about why that is so, since I'm reading this lesson as saying that either the subjunctive or indicative is OK.
Thanks for your help!