The first day back in the classroom went quickly. The half-day for students at Marjory Stoneman Douglas High School in Parkland, Fla., was their first at school in two weeks — but what the day lacked in length, it balanced with heartbreak and hope.For the first time since a gunman claimed the lives of 17 of their classmates and teachers, wounded 14 others and took aim at many more, the survivors gathered again Wednesday to resume studies the killings put on pause.They weren't alone: Police officers, members of the media, grief counselors, therapy dogs and dozens of supporters lined the streets outside, there to cheer the students through the difficult time. The crowds of outsiders were as good a proof as any that Wednesday's series of half-hour periods, which began at 7:40 a.m. and ended by lunchtime, were not about the lessons at the front of the room.They were about recovery."It's just crazy to think it happened to us," sophomore Nick Landry told NPR's Greg Allen on Wednesday. "I haven't gone to counseling myself, but I do know some of my friends that have gone and needed it — and that's a good thing, though."As Greg noted, the students did not return to the building where the shooting occurred. "It's being demolished and replaced," he explained.But that did not ease the weight of their lost classmates' absence. Ethan Trieu, a senior, told NPR on Tuesday that he can tell his friends and fellow survivors are "just not the same — you can tell, just from the way they're talking, they're not the same."Many of them have changed in another, very visible way: In the half-month between the shooting and the resumption of classes, a number of the Douglas students swapped their notebooks for signs and microphones, taking up activism for gun control measures. They planned the March for Our Lives, descended on the state Capitol to push new gun legislation and inspired studentsacross the country demonstrate and speak out as well."Since we've been home, it seems like everyone is part of the movement," Douglas sophomore Gabe Glassman wrote Tuesday for NPR. "I'm speaking, tweeting and writing letters to government officials. And I'm not even one of the organizers."Even as these kept their lives busy, Glassman said, one difficult challenge loomed. "I know it will be hard, just to walk on campus."So many more hurdles remain for the students — but at least now that the school day is done, the first and perhaps biggest one has been cleared."I pray that today is the beginning of our long and difficult journey from grief, sorrow and anger to a new consciousness of hope, compassion and love," Broward County Public Schools Superintendent Robert Runcie tweeted Wednesday."Thank you to our young people for leading the way. Welcome Back!" Copyright 2018 NPR. To see more, visit https://www.npr.org/.