Definition: In this task, you will be given a short story. One sentence from the story is chosen. Consider the events that happen before that sentence, or are likely to have happened before it. Does any of them directly cause it, or simply make it possible? You should write your answer in the form " A >causes/enables> B". Try to use phrases and sentences from the story to compose your answer when possible.
Input: story: My friend Lizzy wanted some gum. She gave me a dollar to go get her some. I went to a corner store to purchase it. I purchased some gum but the total was 25 cents extra. I gave Lizzy her gum, but I didn't tell her I paid extra.
 selected sentence: I gave Lizzy her gum, but I didn't tell her I paid extra.

I purchase some gum >Causes/Enables> I give Lizzy her gum