Sentence 1: Rob needed to bake a cake for someone's birthday. 
 Sentence 3: So he planned to bake the cake late at night 
 Sentence 4:  But he had trouble staying awake 
 Sentence 5:  When he woke up, he realized he never baked the cake 
 Option 1: But it was too hot to turn on his oven. 
 Option 2: He had no ingredients at home, so he bought one from the store instead.