The government has been waging an undeclared war against them for decades.政府数十年来一直在对他们不宣而战。To whom does this undeclared certified mail belong?这件未经申报的挂号信是谁的？ He is an undeclared candidate for the party president.他是该党主席的候选人，但尚未公开宣布。No income should remain undeclared.任何收入都必须申报。