Problem: How does the sentence end?

Michael didn't have nearly the amount of creativity as Nelson, which is why 
Answer: Nelson succeeded at becoming an artist.

Problem: How does the sentence end?

The rock was more special than the stone because the 
Answer: rock was from a unique area on the mountain.

Problem: How does the sentence end?

Katrina showed their large aquarium to Cynthia since 
Answer: Katrina had owned one for a long time.

Problem: How does the sentence end?

The film amused Rebecca the whole way through but not Mary because 
Answer:
Rebecca was laughing the whole time.