Sentence 1: Pete had always wanted his own pet puppy. 
 Sentence 3: He was so happy but didn't know how to train it 
 Sentence 4:  He brought the puppy to a trainer with his parents 
 Sentence 5:  Within a few short months, the puppy was very behaved! 
 Given Sentence 2: That Christmas, his parents bought him a little labrador!