Their identities were kept secret.

他们的身份保密。

《牛津词典》

They also share a common secret: The details of their meetings, even their identities, have been strictly confidential.

他们还有一个共同的秘密：会议的细节，甚至他们的身份都是严格保密的。

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For a long time the Circlemakers kept their identities secret but they now openly claim to have made many hundreds of circles.

过去很长一段时间，怪圈制造者们从不暴露自己的身份。但是现在他们公开地承认制造了数百上千的庄稼圈。

youdao

One of the few surveys on anonymous giving concluded that the primary reason donors like to keep their identities a secret is to avoid getting badgered by fund-raising requests.

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Unidentified Man: Their identities are a secret, even from each other.

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Many of the names of the investment funds participating in TALF have remained a big secret, but the Federal Reserve is required under new financial reform legislation to disclose all of their identities later this year.

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