story: Kate's school had a contest. Whoever could earn the most box tops would win a prize. Kate spent all month finding as many box tops as possible. On the last day of the contest, she turned in her box tops. She ended up winning.
 selected sentence: Whoever could earn the most box tops would win a prize.
Whoever earns the most box tops wins a prize >Causes/Enables> Kate spends all month finding as many box tops as possible