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: Joe was on the bus. He was going to his seat. He then saw and old man who needed a seat. Joe knew what to do. He let the old man sit in the seat.
 selected sentence: Joe was on the bus.

Joe gets on the bus >Causes/Enables> Joe is on the bus