Sentence 1: Cindy's friend was often very mean to her. 
 Sentence 3: They yelled at each other 
 Sentence 4:  Cindy stormed out 
 Sentence 5:  She decided they were no longer friends 
 Option 1: One day, her friend failed to pick her up from the airport. 
 Option 2: One day, her friend said something horrible.