An expression I don't understand This is the excerpt of the book The Body He remembers seeing Johnny get halfway up from the squat he had been working in when the Mustang hit him, squashing him between it and the Chevy, and there had been a hollow bang as the Chevy came down off its jacks, and then the bright yellow flare of flame, the rich smell of gasoline... What does "as the Chevy came down off its jacks" mean?