Given the task definition and input, reply with output. 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.

Sentence1: Joan sent her son on a camping trip with the school. Sentence2: While he was gone, she cleaned out the spare bedroom. Sentence3: She moved all of his things from the room he shared with his brother. Sentence4: She set up his computer and arranged his new furniture.
She opened the door to his new, own, room and yelled, "Surprise!"