請翻譯下面的英文段落（有關(guān)專利的）
In most patent systems, in order to anticipate a claim, prior art is expected to provide a description sufficient to inform the average worker in the field (or the person skilled in the art) of some subject matter falling within the scope of the claim. Prior art must be available in some way to the public, and many countries require the information to be recorded in a fixed form somehow. Again, in most patent systems, prior art does not include unpublished work or mere conversations (though according to the European Patent Convention, oral disclosures also form prior art — see Article 54(2) EPC). It is disputed whether traditional knowledge (e.g. of medical properties of a certain plant) constitutes prior art.