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Psychological training and increased security that many schools instituted after the killing of 13 people in 1999 at Columbine High School in Colorado have given teachers and principals new tools and insights to spot potential trouble , the experts said .
 Colorado, Columbine High School
Please list all entity pairs containing a certain relationship in the given options.Output format is "word1, word2; word3, word4". 
Option: ethnicity, place lived, geographic distribution, company industry, country of administrative divisions, administrative division of country, location contains, person of company, profession, ethnicity of people, company shareholder among major shareholders, sports team of location, religion, neighborhood of, company major shareholders, place of death, nationality, children, company founders, company founded place, country of capital, company advisors, sports team location of teams, place of birth 
Text: {0} 
Answer:
 Colorado, Columbine High School