Breakdown of Si nos hubieran advertido, el colapso del edificio no habría sido tan catastrófico como fue.
ser
to be
de
from / of
no
no, not
el edificio
the building
Questions & Answers about Si nos hubieran advertido, el colapso del edificio no habría sido tan catastrófico como fue.
Why is it hubieran advertido (past perfect subjunctive) instead of habían advertido (past perfect indicative)?
Because this is a past unreal conditional sentence. We are talking about an imaginary past event (they didn't actually warn us). In Spanish, the if-clause (si...) of an impossible or imaginary past situation always triggers the past perfect subjunctive.
Can I use the conditional perfect in the si clause, like Si nos habrían advertido?
No, this is a strict rule in Spanish. While native English speakers sometimes say 'If they would have warned us,' you can never use the conditional perfect right after si in these sentences. The condition always takes the past perfect subjunctive (hubieran advertido), and the result takes the conditional perfect (habría sido).
Does the past participle advertido need to match the plural pronoun nos and become advertidos?
No. When you form compound tenses with the auxiliary verb haber, the past participle never changes its ending. It will always end in -o, regardless of whether the subject or the object pronoun (nos) is plural or feminine.
Why does the sentence end with como fue (preterite) instead of como era (imperfect)?