| 摘要 |
A structured perforated plastic sheet includes a plastic sheet body having bottom ribs in a bottom layer, middle ribs in a middle layer, and top ribs in a top layer. The top ribs are interconnected to define a top hole. The middle ribs divide the top hole into multiple middle holes. The bottom ribs divide each middle hole into multiple bottom holes. Each of the top, middle and bottom ribs has a top wall and two side walls extending downwardly from two opposite sides of the top wall. The side walls of the top and middle walls are deflected in a plane of the top walls of the bottom ribs.
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