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: Barry went camping with some friends. He was the only one in his tent at night. He had a hard time sleeping on the hard ground. His back started to hurt. He quietly got up, packed his things, and drove home.
 selected sentence: His back started to hurt.

Barry sleeps on the ground >Causes/Enables> Barry's back hurts