Sentence 1: Clark had a friend named Kevin who had a crush on some girl he met. 
 Sentence 3: Finally he asked Kevin to introduce him to the girl so Kevin shut up 
 Sentence 4:  Kevin looked at him with his mouth hanging open 
 Sentence 5:  How could Clark not know his own sister! 
 Option 1: Clark was excited  of hearing Kevin talk about this girl. 
 Option 2: Clark was tired of hearing Kevin talk about this girl.