Level 8, the phrase “Are you ready?”. For an English speaker, “you” is the most tricky word to deal with when trying to think in German. It could be singular (du), plural (ihr) or formal (Sie). The correct given answer on the course is “sind Sie bereit?”: but “bist du bereit?” or “seid ihr bereit?” would be equally correct given the question.
I know that courses that try to be extremely precise (for example, the excellent user-created grammar course here: http://www.memrise.com/course/74072/german-grammar-7/) can have questions that look ugly because of their precision. But I think that’s better than letting learners make a “wrong” answer (and then be reminded of it automatically for practice as if it was a problem) just because the question is vague.
How about changing the English entry for this question to “Are you ready? (formal)”