Problem: How does the sentence end?

Going through the television channels, Alexandria skipped the romance series but watched the fantasy one because the 
Answer: romance was boring.

Problem: How does the sentence end?

Running like a wild rabbit helped Adam win the race but not Neil because 
Answer: Adam was very fast.

Problem: How does the sentence end?

Katrina had an electric guitar, and Carrie had an acoustic, so 
Answer: Katrina needed an amp for their instrument.

Problem: How does the sentence end?

Bad posture causes the shoulders to round and the hips to arch. The 
Answer:
shoulders do this because the lumbar spine is curved forward.