distress flag

基本解释

Seeing a ship on the horizon, we ran up a flag of distress.
看到地平线上出现一只船，我们连忙升起遇险信号旗。
dict.cn
Both films end with powerful visual statements: a montage of real people killed in Iraq, the raising of an American flag upside down, as a traditional distress signal to other nations.
在此次影展上的两部影片（原谅我- -还是不知道另外一部）都以大魄力的画面陈述作为结尾：在伊拉克死去的士兵的蒙太奇组接； the raising of an American flag upside down,（求这句的翻译）作为向其他国家发出的求救信号。
blog.sina.com.cn

Denmark's prime minister, Anders Fogh Rasmussen, has no mandate to express his distress to flag-tearing believers in anybody's name but his own.
ECONOMIST: Firm observations