| 摘要 |
The book cover is made from a piece of cardboard with two parallel fold lines between the spine and front and back. The inside surface of the spine is covered with a strip of thermo-setting adhesive. The fold lines are made by using a tool which presses the cardboard against two parallel ridges projecting from a base plate. The adhesive strip is placed between these ridges so that it is bonded to the spine simultaneously with the formation of the fold lines.
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