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.
Q: story: Emma was working on her math homework. She asked her dad to help her. Her dad didn't understand the problem. Emma called her classmate. Emma's classmate explained the problem.
 selected sentence: Emma was working on her math homework.
A: 
Emma is assigned math homework >Causes/Enables> Emma is working on her math homework