The tooth fairy doesn't exist either. Did you really think it did? Guess the course makers aren't the only imperfect ones around here. See what happens when you mock others? Hashem gives us a taste of the same medicine we give others, so we should always be mindful of the effects that our actions have on them.
talguetta, that might be the correct answer and the closest to the Hebrew, but I can’t think of a case where an English speaker would say I don’t find a big suitcase. Ordinarily if I’m searching for a big suitcase in my house or a store and I’m unsuccessful, I will say “I can’t find a big suitcase”.
Duolingo translated lo motse as “can’t find” here and “Where is this page? I can’t find it”, so it seems that Hebrew has a “can’t is understood” idea when “lo motse” appears.
Duolingo accepted “I’m not finding a big suitcase”, which is what a native speaker might might say if he’s in the middle of his search, but that would be an unusual way to say it.
By the way, I’m grateful to Duolingo for changing their former “I can’t find a big luggage” to “I can’t find a big suitcase.”