Exercise 12. add apostrophes to these sentences if necessary 1) is that book yours or sams? - is that book yours or sam's? 2) davids sisters cats name is syrup. 3) have you met pats brothers? 4) are those shoes hers? 5) these are the girls fathers. 6) those are the teachers cars. 7) these sandwiches are ours. 8) my books are in my friends bag. 9) whose gloves are these? 10) that is jacks fathers bike