Problem: Continue the following story.

Stephen wanted to return an item with a receipt but could not. The 
Here's how I want to continue it: item was too used.

Problem: Continue the following story.

She sweetens het tea with honey instead of sugar, because the 
Here's how I want to continue it: sugar is unhealthy for her.

Problem: Continue the following story.

Jennifer is being taught how to play the Mandolin by Erin. 
Here's how I want to continue it:
Jennifer is a Mandolin student.