I've gone through the German lessons one by one, however, my new lesson "Adverbs1" is inactive. Why?
Please provide a screenshot so we can see that what you are saying is the case. You can also try refreshing the page just to be sure it's not a temporary glitch. Odds are you haven't completed all the sub-lessons within the lessons preceding Adverbs1.
If it's a real problem, a lot more people would probably be encountering it by now. However, the Duo team will probably take a look if you include more details/proof of the problem..
I have checked your comments before, but nothing happened. I would appreciate your kind help.
If you're unable to share a screenshot, please post in this Troubleshooting forum and someone from Duo can take a look for you, perhaps - https://www.duolingo.com/topic/647
Most of us here are users like you, so we can't see your screen. There isn't a lot more we can do to help, unfortunately.
Don't be sad. Think of it as additional practice (you would've practiced all those anyway to strengthen your grasp). Good luck!
My guess is that you missed a lesson before that, otherwise it should automatically unlock. Please go back through the rest of the skills and make sure you completed ALL the lessons in each skill.
No, nothing is left. I've done all previous lessons. Now I am getting hopeless.