Problem: How does the sentence end?

Matthew tried to be stealthy while planning a party for Donald, but 
Answer: Donald found out from someone who couldn't keep a secret.

Problem: How does the sentence end?

Samantha had an easy time reading the book but a difficult time reading the note because the 
Answer: note was in French.

Problem: How does the sentence end?

The leggings looked good on Cynthia but looked only okay on Victoria because 
Answer: Cynthia was wearing the right size.

Problem: How does the sentence end?

Ryan's fish tank looks really clean, and Nelson's looks really dirty because 
Answer:
Nelson cleans rarely.