Breakdown of Le soldat a confirmé qu'ils n'avaient vu aucune attaque.
ils
they (masculine/mixed)
avoir
to have
ne
not (used before the verb)
voir
to see
Questions & Answers about Le soldat a confirmé qu'ils n'avaient vu aucune attaque.
Why is avaient vu in the plus-que-parfait (had seen) here?
Because the main verb a confirmé is in a past tense, the reported speech must backshift. If the soldier's original words were in the passé composé ('Nous n'avons vu aucune attaque'), the backshift rules change it to the plus-que-parfait. If his original words were already in the plus-que-parfait ('Nous n'avions vu aucune attaque'), the tense remains unchanged.
Why is the negative n'avaient vu aucune instead of n'avaient pas vu aucune?
Where does aucune go in a compound tense like the plus-que-parfait?
Unlike pas or rien, which usually sit between the auxiliary verb and the past participle (like n'avaient rien vu), aucune modifies a noun directly. Therefore, it stays right next to the noun it modifies at the end of the phrase: n'avaient vu aucune attaque.
Should the past participle vu agree with the feminine noun attaque?
No, because the direct object (aucune attaque) comes after the past participle. In compound tenses using avoir, the past participle only agrees with a direct object if it comes before the verb.