DENVER，COORADO——What does it take to be a hero? In the case of five Denver children，it only takes a cry for help．Here’s the story of these five heroes as Gary Lewis， the man they helped，tells it． “I like to work on my old car．It’s my hobby．I wanted to put a new transmission(传动装置)in the car．I put the car up on blocks(大块木头)because I wanted to get under it．I was trying to get the old transmission out when suddenly the car moved forward and fell off the blocks．It came down on my chest．I couldn’t breathe． “I tried to shout fo