Problem: How does the sentence end?

A recipe called for meat to be cooked in a crock pot but the 
Answer: crock pot was too shallow.

Problem: How does the sentence end?

A spoon of food was served into the baby's mouth but he could not eat it all because the 
Answer: mouth is small.

Problem: How does the sentence end?

The cat could not climb up through the wall so it used the pillar because the 
Answer: pillar is rough.

Problem: How does the sentence end?

Betty but not Rebecca would be a good private investigator because 
Answer:
Betty knew how to go unnoticed in a crowd.