Learn Finnish: Voi ei! Se oli kamala päivä. - Oh no! It was a terrible day.

Oli is the past tense of the verb olla (to be) for the he/she/it form. While se on means it is, se oli means it was. This fits perfectly with the lesson's focus on talking about things in the past.

Why use se instead of hän?

In standard Finnish, hän is strictly used for people (he or she), while se is used for animals, objects, and abstract concepts like a day.

Does the adjective kamala need any special endings here?

No, it stays in its basic dictionary form. Because the noun it describes, päivä (day), is the subject of the sentence and in its basic form, the adjective simply matches it without any extra endings.

Is voi ei a direct word-for-word translation of the English phrase?

Yes! Voi is a common exclamation that acts like oh, and ei means no. Put together, voi ei is used exactly like oh no in English to express dismay or disappointment.