[Q]: How does the sentence end?

William had to replace his chimney cap but Ian did not since 

[A]: William never replaced it before.


[Q]: How does the sentence end?

Craig went shopping at an expensive food store while Kevin went to the food kitchen since 

[A]: Kevin was poor.


[Q]: How does the sentence end?

Everyone wanted to be a mermaid at the Halloween party, but the costume at the store only fit Christine and not Jennifer because 

[A]:
Christine was slender.