Sentence 1: Dan heard that his neighbor had just become a widow. 
 Sentence 3: Dan decided to help the widow financially 
 Sentence 4:  Dan mailed her an anonymous money order for fifty thousand dollars 
 Sentence 5:  To this day, the widow doesn't know who gave her that money 
 Given Sentence 2: Unbeknownst to him, she was allergic to lilies.