If you have some plain text, some message that you want to send, well, you can encrypt it or you can scramble it using a key, a secret key, which might be a physical machine like the Enigma 13 or it might be a number like 13.

如果你有没有加密的文本，你想要寄送的一些消息,你就可以加密它,或者你可以用一个密钥使其变得混乱，那就像一个英格玛的物理装置,或者他就是一个数字。

哈佛公开课 - 计算机科学课程节选

But Putin's message is plain: he is signaling that as Russia gains global prominence it is no longer content to accept Western dominance, including over who heads the IMF and the World Bank.

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Can the message be any more plain, Luke Fickell?

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The message to them is already plain.

ECONOMIST: Russia