Original sentence: The school has a large steel post picket fence surrounding it and has its gates can be padlocked shut to form a fortress during an emergancy lockdown, as happened on the 22 August, 2007 when a formor student threatened students of the school
Edited sentence: The school has a large steel post picket fence surrounding it and has its gates can be padlocked shut to form a fortress during an emergancy lockdown, as happened on the 22 August, 2007