So many keep wondering about the word (name) "Duo" when it first shows up in the lesson. It is not meant to be a German name. It is the name of the mascot owl. I think a lot of confusion would be avoided if the mascot owl at the beginning introduces himself with "Hi, my name is Duo!" (Personally, I think they chose that name because it means "two" in many languages so it refers to learning a second language.)
This part of the german course is awfully made: ive had this question and others similar to this one several times in a row, which is useless and very poor. also, the Duo thing is just pointless, annoying, useless, time wasting, not even amusing. Im sorry i sound so harsh, but duolingo has great potential and sometimes i dont understand why things are not only poorly done, but terribly. Fix it, please. Thanks in advance.