When a user highlights words on the One Drive (iOS), it usually means that the words are important. So, why not developing a tool which allows users to generate a "Quick Recall Test" on the highlighted words?

The system can simply hide the words that are highlighted, and ask the users to fill in the blanks. I believe this function will be very useful for post-secondary school students (like me) to memorize the key concepts. What's more, if possible, the Microsoft can consider storing the results of each test, so the students know what they usually forget or overlook.

I have been using One Drive for 6 years, and I found it much better than its counterparts (Google Drive, Ever note) in terms of its in-app pdf editing function. Keep it up and try to go one step further, I am sure One Drive will dominate the education market.