1.   Although power margins never fell to critical levels, a number of alarms sounded to warn the station crew that the electrical system had been affected.

2.   And early this evening, the siren sounded to warn that shelling might be imminent.

3.   But if your refrigerator door or drawer happens to open, an alarm will sound to warn you.

4.   But what sounds appealing, most Western experts warn, could easily backfire in practice.

5.   Church bells are then sounded to warn the people to flee.