Learn Finnish: Oppivelvollisuus jatkuu, kunnes opiskelija on aikuinen. - Compulsory education continues until the student is an adult.

Yes! Instead of the single conjunction kunnes (until), you could express this same idea using a pronoun bridge with a postposition, such as siihen asti, että or siihen saakka, että (until the point that). Both convey the exact same meaning, but kunnes is often preferred here because it is much more concise.

How is the compound word oppivelvollisuus formed?

It combines oppi (learning) and velvollisuus (duty or obligation). At the B2 level, you might notice that velvollisuus comes from the adjective velvollinen (obliged), which originates from velka (debt). Together, they form the standard term for compulsory education.

Why does the sentence use jatkuu instead of jatkaa?

Jatkuu is an intransitive verb, meaning something continues on its own without a direct object. Here, the education itself just continues. You would use the transitive verb jatkaa if a specific subject were actively continuing an action, for example: opiskelija jatkaa opiskelua (the student continues studying).

Why is aikuinen in the nominative case here rather than the partitive?