Problem: How does the sentence end?

The man could write instructions for building engines but not houses, since
Answer: houses were his area of ignorance.

Problem: How does the sentence end?

In order to keep the schedules in sync the manager wrote them down on paper instead of in a notebook because the
Answer: paper was available.

Problem: How does the sentence end?

The files would load on my PC, but not my Mac, because my
Answer: Mac was incompatible with them.

Problem: How does the sentence end?

Christine decided to make a bowl of strawberry flavored jello for Maria because
Answer:
Christine is very generous.