Problem: How does the sentence end?

The children didn't understand the material from the book so the teacher displayed the video because the 
OPTIONS:
- book was complicated.
- video was complicated.
Answer: book was complicated.

Problem: How does the sentence end?

The violets in the garden of Natalie grew much shorter than Rebecca's because 
OPTIONS:
- Natalie is great at gardening.
- Rebecca is great at gardening.
Answer: Rebecca is great at gardening.

Problem: How does the sentence end?

We removed the plants from the bathroom and added flowers, as the 
OPTIONS:
- plants were making it smell better.
- flowers were making it smell better.
Answer: flowers were making it smell better.

Problem: How does the sentence end?

The care provider had to switch from bandages to gauzes, as the 
OPTIONS:
- bandages were useless against the bleeding.
- gauzes were useless against the bleeding.
Answer:
bandages were useless against the bleeding.