story: I've always wanted to ride on a river boat. The kind with the big water wheel that went on the Mississippi river. I saw one once in an old movie. I guess the water wheel doesn't change much but I bet it's more quiet. I'm saving my money to ride one if I ever get the chance.
 selected sentence: I saw one once in an old movie.
I see a river boat in an old movie >Causes/Enables> I want to ride on a river boat