Problem: How does the sentence end?

Mary wanted to serve wine to her friends but served beer instead because she thought alcohol concentration of the 
Answer: beer was appropriate.

Problem: How does the sentence end?

It is so much easier to remove a wall made of drywall than plaster because the 
Answer: drywall does not crumble.

Problem: How does the sentence end?

Michael was walking slower than Hunter was walking in the park because 
Answer: Hunter had a healthy back.

Problem: How does the sentence end?

Last month Elena went on vacation but not Christine because 
Answer:
Elena had to take time off.