1.   A railway company has instructed its engine drivers that before they go over a crossing, they must sound their whistle, to give warning to anyone crossing.

2.   He peers through fog and storm to give warning of dangers ahead.

3.   In medieval Europe, victims of this disease were forced to wear bells around their necks to give warning of their presence.

4.   Publicly, however, the United States insists the Iraqis have been given ample warning already to cooperate with U.N. weapons inspectors.

5.   The administration has done its best to give warning of the likely effect.