21.   Other cities tout their quality of life while straining to rev economic engines.

22.   Several thought they could see the outline of a German U-Boat that appeared to be stuck on a sandbar, possibly revving its engines to escape.

23.   Sometimes he goes down to the garage where it sits, eases in, grips the wheel and revs the engine.

24.   The cars began revving their engines.

25.   The crowd simultaneously inhales as he revs the engine in preparation.

26.   The two dropped their poles, revved their engine, and called the police while they raced to the Piper Malibu plane, which was sinking fast.

27.   Then over the first hill they came, youngsters storming along the track in multicolored suits, revving their engines along each turn.

28.   They revved their engine and shouted a few obscenities as they tore out, sending dirt swirling around the officers.

29.   When it revs its engines, the volume never rises above a polite hum.

30.   While the flamboyant Mavs trod tentatively with every step, the Kings kept their engines revved at full speed and their eyes on the road.