Problem: Continue the following story.

Christopher practiced fire safety and Derrick did not, so 
Here's how I want to continue it: Christopher remained calm when the fire alarm at the office building went off.

Problem: Continue the following story.

Randy was a teenager that liked sports while Craig was a teenager that liked debate because 
Here's how I want to continue it: Craig was clever.

Problem: Continue the following story.

William liked to keep the house clean, but Robert was filthy, so 
Here's how I want to continue it:
Robert was always leaving things lay around.