31.   New software that helps highlight school trouble spots may help educators trying to avert violent episodes such as the Columbine High School shootings earlier this year.

32.   The half-hour battle was the most violent episode in a four-day crisis that has paralyzed this South American country and sorely tested its decade-old democracy.

33.   The half-hour battle was the most violent episode in a four-year crisis that has paralyzed this South American country and sorely tested its decade-old democracy.

34.   The pair of violent episodes provoked outrage and warnings of retaliation on both sides.

35.   The shooting was in stark contrast to recent incidents in at least four other communities, where students reported threats and averted violent episodes at school, authorities said.

36.   There have been at least four incidents around the country in recent months where students reported threats and possibly averted violent episodes at school.

37.   Anum said the recent clashes were only the latest in a series of violent episodes between the Dayaks and the Madurese.