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: Kelly bought a book to read on a plane one day. Sentence2: She had two long flights and nothing else to do. Sentence3: She became engrossed in the book as she flew. Sentence4: But when she changed planes, she realized she'd forgotten it!

Kelly was unhappy.