Sentence 1: Sam wanted to get a dog. 
 Sentence 3: It just so happened he logged onto Facebook to see an ad for a pound 
 Sentence 4:  A dog named Grump was going to be put down that day 
 Sentence 5:  Sam has a new best friend named Grump, you should meet him 
 Given Sentence 2: So he was researching local pet stores to buy one.