His mission is to help poor children. = He has made it his mission in life to help poor children. = He's a man with a mission: to help poor children.他的人生使命是帮助贫困儿童。He viewed his mission in life as protecting the weak from the evil.他认为自己毕生的使命就是保护弱者不受邪恶势力的欺凌。He viewed his mission in life as protecting the weak.他认为自己的天职就是保护弱者。