信号的方向指明最佳通过周围有障碍物急流的通道.Paddle blade should be turned flat for maximum visibility.'水沟'.''推动磨坊水轮的急流的''.'水沟'. ''.The channel for the water that drives a mill wheel.当你的皮船和木筏冲...

“急流的”的英语可以翻译为：ushing ...