I used to think A, but now I know B.

I recently had my students use a writing prompt from Figment.com where they fill in the blanks in this sentence, then write a story. 

I've discovered that it's a really good way of reflecting on learning. For example.

I used to think: Hard working, caring teachers could save the world, one student at a time.
But now I know: They can't without major changes in economic and education policy.

I used to think: My PhD would not help me be a better educator.
But now I know: It does.