I am not sure which language pair you are learning.
And - I support you [mention]c_renfrow524[/mention]
Also, I do not know if I can help you. I do recommend you take time to read the guidelines/tips/hints that Duo provides for the course you are studying.
Yet - I would love to see the Duo course allow learners to have greater control also over their learning. For many of us, we are learning from various other sources, and also for many other reasons. Sometimes it is also to pass a special test set in a school environment. Or, for some to negotiate a real life situation that is coming up, or has been experienced. Or for educators, to assist a learner in an area they see the student may be struggling with.
That is why I also seek to share the resources I create for English speakers learning French. The language pair I am most interested in.
I do hope others may assist you in a more relevant way with you query. I am glad you are in our community and adding to learning, by asking good questions.