As an intermediate to advanced learner, I want to be able to see terms I know while and fill in a missing tone, so that I can work on my tone recognition.

[CharlieMcVicker]

• [ ] Only use terms the user is confident with
• [ ] Only show as an option if there are plenty of valid terms
• [ ] Don't update learning progress when lesson is over, maybe track progress independently

[CharlieMcVicker]

closed by #76