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: Mable knew she couldn't mow her lawn at her advanced age. She went next door and asked the neighbor boy if he would do it. The boy agreed and mowed her lawn for her. When Mabel went to give the boy money he wouldn't take it. Mable shed a tear from the boy's kindness.
 selected sentence: Mable knew she couldn't mow her lawn at her advanced age.

 Mable was old >Causes/Enables> Mable can't mow her lawn