A middle school class went on a field trip to the construction site.

Suddenly, a worker falls to his death from the roof of an unfinished building. Because of this, the school decided to hold an accident prevention class. The teacher asks: "Children, how do you think, why did that man fall?" "He was standing too close to the edge of the roof!" - said Lily. "He was drunk!" - said Billy. "Both of you are wrong," said Johnny, "he fell because he was badmouthing my mother! I heard him yell, "Hey, you son of a bitch! Stop shaking the ladder!""