speedcopn.<俚>制止汽车超速行驶的警察speedn.速度；迅速v.加速；急行speed of perception知觉速度,感觉速率speed of ultrasound超声速度speed changing gear变速齿轮speed-measurement测速speed-droop ratio速度变动率speed-change gear变速机构speed of sound wave声波速度speed closed-loop速度闭环speed cutting steel高速切现speed control valve调速阀