In a document copying machine, a means by which parts of the image of the original is obscured so that it is not produced onto the copymaterial.
文件复印机上使用的一种方法，将原件映象的某一部分掩盖起来，使其不复印到复印件上。
2
Please make a copy of this material.
请你把这个材料照抄一份。
《新英汉大辞典》
3
The evidence they have now collected suggests it was last November that somebody working in a high-security facility inside a US military base in Iraq started to copy secret material.