Sentence 1: My three year old son and I decided to mow the lawn. 
 Sentence 3: He sat on my lap and played his Ipod while I drove 
 Sentence 4:  I noticed he had stopped playing after a few minutes 
 Sentence 5:  I looked down and he was sound asleep in my lap 
 Given Sentence 2: We checked the oil and filled the gas tank.