Problem: How does the sentence end?

Lindsey was given the silent treatment by Amy because she was angry; 
Answer: Amy didn't speak to her for two days.

Problem: How does the sentence end?

Cynthia prefers a gas grill while Monica does not since 
Answer: Monica likes the smoky flavor of a charcoal grill.

Problem: How does the sentence end?

I want to use the silk thread instead of the synthetic thread for this embroidery project because the 
Answer: synthetic thread is low-quality.

Problem: How does the sentence end?

Having grey hair bothered Benjamin but Michael liked it. 
Answer:
Benjamin thought it made them look very old.