This sentence is closed to questions on the main Duolingo site. I've spent the last half hour trying to understand why the first word is "bifile" instead of "bifil". I think I've concluded that it is an adjective being used as a noun but wouldn't "de" be in front of it? ordbok.uib.no doesn't have any form of the word nor does Haugen (not surprisingly, since it's old).
Can someone point to where I could find the information I'm looking for or answer my question? Thank you.