Breakdown of Ella se comporta como si fuera la dueña de la casa.
ser
to be
ella
she / her (after a preposition)
la casa
the house / home (also "at home")
de
of
Questions & Answers about Ella se comporta como si fuera la dueña de la casa.
Why does this sentence use the imperfect subjunctive (fuera) when the main verb (se comporta) is in the present tense?
The phrase como si (as if) introduces a hypothetical or unreal situation. In Spanish, como si is always followed by a past subjunctive, never a present subjunctive or present indicative. Because her behaving and the hypothetical ownership are happening at the same time, we use the imperfect subjunctive (fuera).
Could I use fuese instead of fuera here?
Yes. The imperfect subjunctive has two valid sets of endings: -ra and -se. Therefore, fuera and fuese are perfectly interchangeable here, though the -ra form is much more common in everyday spoken Spanish.
Why is there a se before comporta?
The verb meaning 'to behave' is the reflexive verb comportarse. If you drop the se, the non-reflexive verb comportar changes meaning to 'to entail' or 'to involve'.
If I changed the sentence to the past ('She behaved as if...'), would fuera change to a different tense?
No, it would remain fuera. If the hypothetical action happens at the exact same time as the main verb, you always use the imperfect subjunctive, even if the main verb is in the past: Ella se comportó como si fuera la dueña. You would only use the pluperfect subjunctive (hubiera sido) to say she behaved as if she 'had been' the owner at an earlier time.