Problem: How does the sentence end?

Katrina was comfortable presenting the group project, but Sarah blanched at the idea because 
Answer: Katrina had experience speaking in public.

Problem: How does the sentence end?

Rebecca wiped her glasses with a rag and then switched to a tissue, because the 
Answer: tissue would get the job done.

Problem: How does the sentence end?

The beam could no longer support the roof, as the 
Answer: beam was too weak for it.

Problem: How does the sentence end?

Rebecca taught Samantha about mushroom picking because 
Answer:
Samantha was ignorant about which ones were edible.