Complete the time-traveler's rather confusing diary entry.

I am stuck in 1899. I ______ my time machine's keys yesterday, and now I'm living in a barn with a very confused horse.

The correct answer is lost.

In English, when a sentence includes a finished time word like "yesterday," "last week," or "in 1999," you must use the Past Simple (lost).

Note for Romance language speakers: Even though your native language might use a perfect tense here (like he perdido, j'ai perdu, or ho perso), English strictly separates finished past time from the Present Perfect!