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: Once there was a mother who was desperate for her baby to sleep. Sentence2: She walked him around but still he did not sleep. Sentence3: She fed him but still he did not sleep. Sentence4: Finally, she remembered the lullaby her mother had sung to her.

The mother gently sung the lullaby to her baby.