This exercise was audio. I did not hear the speaker say "an" and I listened more than once. So I chose 'tha t-ord seo trom.' What was really weird is that the Duolingo message said "Correct!" but it was in red and marked me wrong. If I missed hearing the "an" -- OK, mark me wrong, but don't tell me I'm correct AND mark me wrong! That's just messing with my mind, LOL!