Problem: How does the sentence end?

Megan had much thicker skin than Rebecca so
Answer: Rebecca was saddened by people's vile insults.

Problem: How does the sentence end?

Derrick paid for their dinner but Steven wanted their's for free because
Answer: Derrick was generous.

Problem: How does the sentence end?

Joel preferred to drive when Christopher was in the car, since
Answer: Christopher was a very shaky driver.

Problem: How does the sentence end?

When the doorbell rang, Donald opened the door and greeted Joel.
Answer:
Joel was attending his party.