Why in the world are there no direct lessons on conjugations of verbs? I'll be going through the lesson and there'll be BAM, random new conjugation out of absolutely nowhere. I think this site needs some direct lessons on conjugations, because just throwing them out into the open without any previous explanation is not really all that effective. It's been a few years since I last studied French, and it's incredibly frustrating when I can't remember every conjugation or get marked down for putting the wrong one when I've only seen it maybe once.
Maybe you should focus on the fact that Duolingo's mission is to offer English translations of Wiki to non-French speakers. Therefore, you may not want to limit your learning process to the exclusive use of Duolingo. Many Website are out there to complement your knowledge with appropriate lessons on grammar, conjugations, etc. And if you go down the Question section, you will find many links provided by other Duo-leaners to help you.