What does triumph and tragedy in history mean

Triumphant; victory; conquest.

Tragedy: A lamentable, dreadful, or fatal event or affair; calamity; disaster: stunned by the tragedy of so many deaths.

answer:

the majority of cambodians living today were born after the khmer rouge was ousted in 1979 and some who survived can forget how bad it was. when khmer rouge forces seized phnom penh on april 17, 1975, the couple was living with eight of their children in a rural town called kampong chhnang.

explanation:

d. japan's attack on pearl harbor