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1·Ladder feet are in good condition, e. g. rubber tips on metal rolling ladders. Safe-Hi feet on extension ladders.

梯子脚底是否有很好的止滑垫片。如金属梯子脚底的橡胶，延伸梯的防滑垫片。

2·The concept of ladder plane partition is introduced which may be regarded as a natural extension of the shifted one.

作为移位平面分拆的自然拓广，本文引入了梯形平面分拆的概念。

3·The invention provides a self-locking extension working platform of a lifting working ladder, wherein the extension working platform has self-locking function.

本发明提供了一种升降工作梯的延伸工作平台，其延伸工作平台具有自锁功能。