Sentence 1: Wendy was on her computer one night. 
 Sentence 3: An investigation revealed no possible source for the sound 
 Sentence 4:  Still, all night the sound persisted 
 Sentence 5:  Wendy concluded that it must have been a ghost 
 Option 1: She started to hear a weird sound in her hallway. 
 Option 2: She was chatting online with John.