He was working under the flag of the United Nations.

他在联合国工作。

《牛津词典》

YESTERDAY the flag of South Sudan was raised in front of the United Nations in New York.

昨日，南苏丹的国旗在纽约联合国总部前面冉冉升起。

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And here at the United Nations, the new flag of a free Libya now flies among the community of nations.

WHITEHOUSE: President Obama Salutes the People of Libya

Yet our nations show that hundreds of millions who hold different beliefs can be united in freedom under one flag.

WHITEHOUSE: Indonesia��s Example to the World