knockv.敲击；互撞；攻击n.敲；敲门；敲打knocked-onadj.打出的knock-backn.拒绝; 挫折knock device声音信号knock it off别再讲下去； 停止； 停做knockreducern.抗震剂knock-freeadj.非爆震的knock out ofv.从 ... 中敲出来knock-wave冲击波knock sensor爆震传感器knock a ball拍球