Sentence 1: Tom's car wasn't working right. 
 Sentence 3: The mechanic looked at his car 
 Sentence 4:  Then, he told Tom how much it would cost him to get it fixed 
 Sentence 5:  Tom was very surprised at how much money it would cost 
 Option 1: So he decided to take it to a mechanic. 
 Option 2: He decided to look under the hood and figure out what was wrong.