Breakdown of Kaikki olivat vihaisia, koska joku ei ollut huomannut virhettä.
olla
to be
koska
because
vihainen
angry
ei
no / not (en, et, ei, emme, ette, eivät)
Questions & Answers about Kaikki olivat vihaisia, koska joku ei ollut huomannut virhettä.
How is the negative pluperfect tense built in ei ollut huomannut?
It is formed using the conjugated negative verb (ei) + the past participle of the verb olla (ollut) + the past participle of the main verb (huomannut). Since the subject joku is singular, both participles end in -nut.
Why do we use the plural verb olivat and the plural adjective vihaisia with kaikki?
In English, "everyone" is treated as singular (everyone was). However, in Finnish, when kaikki refers to people, it acts as a plural subject. This means the verb must be plural (olivat) and the describing adjective must be in the plural partitive (vihaisia).
Why is the object virhettä in the partitive case here?
The rule is that the object of a negative verb almost always takes the partitive case, and here the action is negative (ei ollut huomannut). Virhe is a word ending in -e, so its partitive ending is -ttä.
Since the clause has a negative verb, why do we use joku (someone) instead of kukaan (anyone/no one)?
If we used kukaan, the clause would mean "because NO ONE had noticed." Using joku means that there was a specific, unnamed person (someone) who failed to notice it. The existence of the person is positive, even though their action is negative.