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: One day, Billy's family went on a trip to the zoo. Billy went to see the lion's den with his sister. Billy walked up to the den and tapped on the glass. One of the lions leaped into the air and swung a paw at Billy. Billy was scared to approach any other animals from then on.
 selected sentence: One of the lions leaped into the air and swung a paw at Billy.

Billy taps on the glass >Causes/Enables> The lion swings a paw at Billy