| 释义 |
〔speed〕The limit of this quotient as the time of travel becomes vanishingly small; the first derivative of distance with respect to time.瞬时速度：当运动时间小到可以忽略时，此商数的极值；距离相对于时间的一阶导函数〔rung〕A rod or bar forming a step of a ladder.梯级：形成梯的一阶的木棒或木板〔stair〕One of a flight of steps.一段或一阶台阶〔stair〕Often stairs A series or flight of steps; a staircase. 常作 stairs 一段或一阶楼梯；楼梯 |