Videos posted on Youtube showed a small but determined group of protesters using chains and long metal pipes to bring down a section of concrete wall blocking one of the entrances to Cairo's Tahrir Square.

上传到Youtube的这段视频显示一个规模虽小但信心十足的群体抗议者们使用链子和长金属棒来破坏阻挡着开罗的解放广场入口的一段混凝土墙。

Radial gates control how much water is released and massive  concrete blocks at the bottom of the chute, called dentates, disperse the flow to reduce erosion as  it crashes into the Feather River.

径向闸门控制释放的水量，滑槽底部的巨大混凝土块（称为齿状）可以分散水流，以减少水流流入羽毛河时的侵蚀。