Sentence 1: Rick's neighbors moved away. 
 Sentence 3: A little yellow cat poked his head through the curtains 
 Sentence 4:  The neighbors had left their pet behind 
 Sentence 5:  Rick opened a window, and took the little cat home 
 Option 1: Weeks later, someone else moved in. 
 Option 2: Weeks later, he saw the curtains in their house move.