Problem: How does the sentence end?

He tried to use the vacuum the clean the office but the
Answer: vacuum was too old.

Problem: How does the sentence end?

Brian had a hard time cutting the food but not Nelson because
Answer: Nelson had a sharp knife.

Problem: How does the sentence end?

The man with cancer chooses surgery over chemo based on his doctor's advice.
Answer: surgery must succeed more in cases like his.

Problem: How does the sentence end?

Betty bought a container for Lindsey for her birthday because
Answer:
Lindsey needed one to store.