He was working under the flag of the United Nations.

他在联合国工作。

《牛津词典》

Ships shall sail under the flag of one State only.

船舶应仅悬挂一国的旗帜航行。

youdao

Under the flag of the "Rising Sun" all Chinese are forced to be docile subjects, beasts of burden forbidden to show the slightest trace of Chinese national spirit.

在太阳旗下，每个中国人只能当顺民，做牛马，不许有一丝一毫的中国气。

youdao

The two commanders met under a white flag of truce.

VOA: special.2009.11.19

"That's why the New York Yacht Club kept the Cup for 130 years, " says Koch, who competed under the flag of the San Diego Yacht Club.

FORBES: Magazine Article

According to an AFP source in Riyadh, in these brigades, under the flag of Al-Qaeda, are citizens of Algeria, Egypt, Tunisia, Saudi Arabia, and also Chechyna.

FORBES: Chechen Volunteers in Syria and the Dangers of Intervention

The biggest threat to their chances of winning will come from an all-English trio of Jamie Staff, Matt Crampton and Jason Kenny competing under the flag of sponsors Science in Sport.

BBC: SPORT | Other Sport... | Cycling | Pendleton sets new British record