Task: Text Completion
Input (English): Sentence1: Laura has always loves swimming, but she has never tried backstroke. Sentence2: She usually avoids backstroke because doesn't want water in her ears. Sentence3: She finds that she loves backstroke and doesn't get water in her ears. Sentence4: From then on, she swims the backstroke constantly.
Output (English): 3, One day she decides to take backstroke lessons from an expert swimmer.