This was after the Columbine High School shootings in Colorado.

写文章的时间就处在卡罗拉多高校枪击案之后。

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In Littleton, a year ago, the two teenage shooters stood apart, alienated from the 10 jock culture that infused Columbine High School.

一年前在小顿城的哥伦拜中学，同伴圈子的孤立将两名少年变为杀手。

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In April 1999, a pair of students at Columbine High School in Colorado killed a dozen fellow students and one teacher, as well as themselves.

1999年4月的一天，两名学生冲进美国科罗拉多州哥伦拜高中，在枪杀12名学生和1名教师后自尽。

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An armed guard watching Colorado's Columbine High School in 1999 was unable to prevent the slayings.

CNN: NRA clarifies its stance on arming schools

In the April 20, 1999, Columbine High School shootings, Harris and Klebold had clearly done significant planning.

CNN: Rejection, bullying are risk factors among shooters

After the Columbine High School shootings in 1999, Colorado lawmakers successfully introduced background checks for buyers at firearms shows.

BBC: Colorado introduces landmark gun laws