Avenge is a verb; revenge is (usually) a noun. * avenge 为动词，revenge 通常作名词。

• People avenge something or avenge themselves on somebody. 报某事之仇用 avenge something，向某人报仇用 avenge oneself on somebody：◆She vowed to avenge her brother's death. 她发誓要为哥哥之死报仇。◆He later avenged himself on his wife's killers. 他后来向杀害他妻子的人报了仇。 You take revenge on a person. 报复某人用 take revenge on。
• In more formal or literary English, revenge can also be a verb. People revenge themselves on somebody or are revenged on them (with the same meaning). 在较正式或文学用语中，revenge 亦可作动词。revenge oneself on somebody 或 be revenged on somebody 意思相同，均表示向某人报仇：◆He was later revenged on his wife's killers. 他后来向杀害他妻子的人报了仇。 You cannot revenge something. 不能说 revenge something：◆She vowed to revenge her brother's death.