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: Charles wanted to color in a coloring book. The problem was he had no crayons though. His mom took him to the store and they both chose a crayon set. When he arrived home he began to work on the coloring book. Charles think his mom forgetting the crayons for him.
 selected sentence: When he arrived home he began to work on the coloring book.

Charles's mom buys crayons for Charles >Causes/Enables> Charles colors in his coloring book