Sentence 1: Justin had a crush on Kate from the moment he saw her at school. 
 Sentence 3: At the school dance, Justin saw Kate sitting quietly by herself 
 Sentence 4:  Summoning every bit of his courage, Justin asked her to dance 
 Sentence 5:  Kate said yes 
 Option 1: Kate smiled at him and introduced him to her boyfriend. 
 Option 2: Kate always smiled and said hello, but Justin could only blush.