Definition: In this task, you're given a four sentences of story written in natural language. Your job is to complete end part of the story by predicting appropriate last sentence which is coherent with the given sentences.
Input: Sentence1: Donna realized it was finally time to potty train her son. Sentence2: She went and bought him a training toilet and pull ups. Sentence3: She worked with him by showing him how to use the potty. Sentence4: He really struggled and didn't seem to understand.

One day Donna saw her son use his potty on his own.