"We were interrogated by the police."
Translation:Vi blev förhörda av polisen.
I really love how very regular the Swedish grammar is :). There are languages with more exceptions than rules (I'm looking at you, Italian and Polish) and having a very regular language enables me to focus on the vocabulary. Also it's very motivating because it's not like one has to learn every little piece by heart but can make very large clusters :)
It's because blev (past tense of bli) indicates that you turn enter another state, like become in English but much more commonly used. That's why it is one of the two ways of constructing the passive voice, the other being adding an -s to the end. In colliquial and more dialectal usage, you can hear vart (not var) instead of blev. This is a what I think is called a defective verb, since it only exists in the preterite. Comparison of the different passive voices:
- Vi blev förhörda - bli + supine
- Vi vart förhörda - vart + supine (colliquial)
- Vi förhördes - preterite + -s