With this method,the printmaker cuts or etches an image onto a piece of metal.

VOA: special.2009.09.02

And so this doesn't know how to do it, it doesn't have a method to deal with it, so it complains.

因为，我原来是期望做什么来着？,我原来是要对x坐标，和y坐标进行对比的。

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