Amy asked Christine to take care of her children for the day, because 
OPTIONS:
- Amy owed her a favor.
- Christine owed her a favor.
Christine owed her a favor.

Since Nick loved animals while Kevin was afraid of them, 
OPTIONS:
- Nick had no pets at home.
- Kevin had no pets at home.
Kevin had no pets at home.

Leonard wants to get rid of his old van and buy a new car because the 
OPTIONS:
- van gets fantastic mileage.
- car gets fantastic mileage.
car gets fantastic mileage.