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: Tom decided to drive to his girlfriend's house today. Sentence2: He drove as fast as he can although there was a lot of traffic. Sentence3: When he got into the front of the house, he rang the doorbell. Sentence4: No one answered however, the front door was open.

Tom began to worry.