knockonn.撞击(打出的粒子)adj.撞击的(被打出的粒子)knockv.敲击；互撞；攻击n.敲；敲门；敲打knock-on collision迎面碰撞,直接碰撞knock off an article赶写一篇文章knock one's lock offknock about together同 ... 厮混knock down a machine把机器拆卸开来knock yourselves outvi.尽最大的努力knock sb's socks offknock themselves outvi.尽最大的努力knock characteristic抗爆特性knock-on certaintyn.必然会产生的事情