Problem: How does the sentence end?

Katrina helped create a practical working budget for Elena's income so that
Answer: Katrina could feel useful.

Problem: How does the sentence end?

The woman took many photographs of the statue, but only 1 of the fountain, because the
Answer: fountain was common.

Problem: How does the sentence end?

Nick found it very easy to learn chemistry but Christopher did not because
Answer: Christopher was quite stupid.

Problem: How does the sentence end?

Lawrence was thirsty and Nelson had a bottle of water, so
Answer:
Nelson gave the bottle to them.