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: My son fell asleep for his afternoon nap. I tiptoed through the house so that I wouldn't wake him. The doorbell rang. I opened the door, but nobody was there. I closed the door and my son woke up.
 selected sentence: I closed the door and my son woke up.

My son falls asleep for his afternoon nap >Causes/Enables> My son wakes up 