The two parties reached a secret agreement long ago.

双方早有默契。

《新英汉大辞典》

Collusion in judicial proceedings is a secret agreement.

在司法程序中，通谋是指一项秘密协议。

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Yang Zhijun and Jack. London have reached a secret agreement in the depth of their heart through animal novels to realize life fantasy, as an expression of human mind.

杨志军与杰克·伦敦有着灵魂的契合，他们借着动物小说完成了人类的生命幻想，成为人类心灵的表达。

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Whether or not there was a secret agreement, this is what actually happened.

ECONOMIST: The unchosen people | The

It turns out that, in 1995, Vice President Al Gore signed a secret agreement with then-Russian Prime Minister Viktor Chernomyrdin "which essentially exempted Russia from American sanctions on arms deliveries to Iran, " sanctions that were ironically required pursuant to a statute Mr. Gore co-sponsored when he served in the U.S. Senate.

CENTERFORSECURITYPOLICY: When Security Fails

In the project's first phase, from 1956-59, the Soviets provided support to China via a secret bilateral agreement on defense technology.

CNN: ASIANOW - TIME Asia | Visions of China: Lop Nor