The conditional perfect passive (olisi tehty)

The Conditional Perfect Passive

When imagining alternative histories—like how ancient architectural wonders might have been constructed differently—we use the conditional perfect passive. This structure expresses what would have been done in the past by an unspecified group of people.

Forming the Conditional Perfect Passive

Creating this form is straightforward. It consists of the auxiliary verb olisi (the third-person singular conditional of olla) followed by the passive past participle of the main verb. The passive past participle always ends in -tu or -ty.

VerbPassive Past ParticipleConditional Perfect PassiveMeaning
tehdätehtyolisi tehtywould have been made
rakentaarakennettuolisi rakennettuwould have been built
suojatasuojattuolisi suojattuwould have been protected
koristellakoristeltuolisi koristeltuwould have been decorated

In affirmative passive sentences like these, the object (the thing being built or protected) typically appears in its basic nominative form. Additionally, when stating what material something would have been built out of, Finnish uses the elative case (-sta/-stä).

This pyramid would have been made out of concrete.
Tämä pyramidi olisi tehty betonista.
The new foundation would have been built from concrete and steel.
Uusi perustus olisi rakennettu betonista ja teräksestä.

When describing what something would have been decorated with, use the adessive case (-lla/-llä) to indicate the instrument or material.

The dark chamber would have been decorated with gold.
Pimeä kammio olisi koristeltu kullalla.

You can use this structure to talk about hypothetical outcomes or plans that were interrupted by historical events.

When the war started, the bridge would have been destroyed.
Kun sota alkoi, silta olisi tuhottu.

Finally, in spoken or highly colloquial Finnish, you will often hear olisi shortened to ois. The grammar and meaning remain exactly the same!

I know that that chamber would have been decorated immediately.
Mä tiiän, et toi kammio ois koristeltu heti.