| 摘要 |
The present invention is directed to a sheet holder, a first panel defining a first window having a first window area, and a second panel defining a second window having a second window area. The first and second panels are joined by at least one hinge, such that the first and second panels are foldable about the hinge to a folded position with the first panel disposed over the second panel. In the folded position, the first and second windows are in overlap with each other such that the first window area overlaps substantially less than the entire second window area. |
