Problem: How does the sentence end?

Kat liked to go swim at the pool instead of at the lake because the 
Answer: lake was murky.

Problem: How does the sentence end?

Tanya was very good at driving a stick shift but Betty was not. 
Answer: Betty failed their driving exam.

Problem: How does the sentence end?

The hat Jeffrey got Jason for their birthday was too big, so 
Answer: Jeffrey kept it for themselves.

Problem: How does the sentence end?

Rebecca is on the computer all day, though Felicia prefers to be in the outdoors. 
Answer:
Rebecca is an indoor person.