Употребить нужную форму притяжательного местоимения. 1) (their, theirs) boat was faster than (our, ours). 2) (their, theirs) home is pretty but (our, ours) is prettier.

1) Their boat was faster than ours.
2) Their home is pretty but  ours is prettier.

Their boat was faster than ours.their home is prettier but ours is prettier