Too many questions repeated; "Last seen" is inaccurate
Great job! I love Duolingo and have used it every day since I signed up 2 weeks ago! (15 day streak!)
I've noticed that I keep getting the same set of sentences, words and questions, when I do "Practice all Skills" in French (words such as aimer, manger, pain, manteau, chien etc.), which I already know perfectly. When I checked the vocabulary section, even if I saw those words 1 minute ago in an exercise, it says I last saw them 1 or 2 weeks ago, so I had to go in and manually remove them from practice.
On the other hand, words which I really haven't seen in a while (like poser, which popped up today and surprised me, because I hadn't seen it in a long time) rarely show up in the exercises. I think you might be recording "Last seen" and "Times Seen" incorrectly; this might affect which practice questions are presented.
It is the same in Spanish. I have translated "Mi padre no es muy viejo" way too many times... The system is really struggling to figure out which words I actually have difficulties with! I also notice in 'practice all skills' it sometimes presents the same phrase (one way or another) 4 or 5 times in the one go!
Happens to me in German too. "Practice weakest words" invariably gives me about 5 sentences with "Zeitung" highlighted. Every time.
Yes! The sentences "Il faut du pain" and "Il faut du lait" show up a lot (I've seen them 20+ times, I think) on my French practice sessions, for example.
I have the same problem with Italian. The same sentences appear again and again and again whenever I practice all skills or the weakest words.
But you can also choose the words you don't know very well and do the exercises just on those individual words. You can also sort the vocab list by strength to see which words it thinks you aren't as strong in. I ignore the time clock and focus on how many bars each word has.