N a series of steps in a river designed to enable salmon to bypass a dam and move upstream to their breeding grounds 鲑鱼梯子; 河中设计系列阶梯，使鲑鱼能够游过河坝，运动到上游产卵地带
N（名词） a series of steps in a river designed to enable salmon to bypass a dam and move upstream to their breeding grounds 鲑鱼梯子; 河中设计系列阶梯，使鲑鱼能够游过河坝，运动到上游产卵地带