story: Carla and Sam spent the morning building a sand castle. They wanted it to be the best one on the beach. They took a break for lunch. When they came back it was gone. The tide had rolled in, smashing it.
 selected sentence: They wanted it to be the best one on the beach.
Carla and Sam want their castle to be the best >Causes/Enables> Carla and Sam yry to make their castle the best