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: John had worked hard on his homework but couldn't find it anywhere. Sentence2: Then he came upon some paper scraps on the floor. Sentence3: His dog, Betty, was sitting nearby with a paper scrap in her mouth. Sentence4: John was worried his teacher would think he was lying.

John didn't know what to do.