Classrooms across the country are still trying to return to a sense of normalcy nearly one month since a gunman killed 17 people at South Florida's Marjory Stoneman Douglas High School.
NBC News created a questionnaire to gauge from teachers what's changed for them since the shooting and how their students are handling it.
Their answers reflected a deep sense of anxiety about what, if anything, they can do to stop a shooter in their own school.
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"I think about what I could do to protect my students, while also understanding any number of them could be the shooter," said one teacher from League City, Texas.
Another teacher talked about keeping a can of wasp spray under their desk.