QUES: Continue writing.

Mary had to clean their house more often than Sarah did because 
+++++++++
ANS: Mary had a cat in their house.


QUES: Continue writing.

Amy likes pretending to be a ninja, and Betty feels too old for that, so 
+++++++++
ANS: Betty is likely the adult.


QUES: Continue writing.

The sweater Robert used last night was more stylish than the one Eric used because 
+++++++++
ANS: Eric  is an old-fashion person.


QUES: Continue writing.

Two different methods to help the blind people at the shelter, Maria raised money for it while Natalie preferred to do work for it because 
+++++++++
ANS:
Natalie was a volunteer.