Problem: How does the sentence end?

The professor gave Nick but not Logan an A because 
Answer: Nick showed extensive knowledge of the periodic table of elements.

Problem: How does the sentence end?

The art store sold lots of canvas but very few frames, as 
Answer: frames were so expensive.

Problem: How does the sentence end?

Jeffrey was the receptionist for the company while Derrick was the data clerk because 
Answer: Derrick disliked to work with people.

Problem: How does the sentence end?

Wanting to be comfortable, the woman placed a pillow on the sofa because the 
Answer:
sofa was stiff.