21.   I park the car in one of the large parking areas where Tombstone Canyon meets Main Street and set off to explore the town a bit before dining.

22.   In Fallingwater, long banquettes upholstered in warm-colored fabrics line the windows, making a stripe of bright that sets off the expanse of green outside.

23.   Investigators are still trying to figure out what set off the air bags, but theorize that Trimbach unknowingly hit a control device while using heavy extrication equipment.

24.   Its pinwheel pattern of apple slices is appealing, and the creamy almond filling sets off the fruit nicely.

25.   Just consider the incident Monday that set off this storm.

26.   Keen walked through dry Johnson grass and set off a cloud of grasshoppers.

27.   Less commonly, Heaton said, a magnitude two earthquake sets off a magnitude three earthquake and so on up the scale of earthshaking power.

28.   Moreover, OPEC members fear that yet another increase would lead to a glut of petroleum early next year and set off a crash in the price of oil.

29.   Merely the hint of help has set off a wild frenzy in financial markets hard-hit by the crisis.

30.   Much of the discussion centered on contrasting views of what set off the instability.