First off: Thanks Duolingo team. You've definitely created the best language learning tool I've come across so far.
Just a general suggestion: It would be great if there was a way to just focus on one type of "problem" for a refresher lesson. At the minute I feel I'm really nailing reading Spanish and then translating this back into English (my native language), but I am struggling with the other way around. If there was a way I could focus on this area once a day on top of my usual "practice all skills" habits it would definitely help my progress. Even if there was an "English" column on the vocab page I guess I could make my own lesson from looking at that.