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: Jim's son is afraid to fly. He's seen too many stories about plane crashes. He can't sleep the night before they are set to fly to Denver. But by the time he gets on the plane he is exhausted. He is so tired that he sleeps all the way through the flight.
 selected sentence: He is so tired that he sleeps all the way through the flight.

Jim's son gets on a plane >Causes/Enables> Jim's son sleeps through the flight