1）knock at（介词at表示的隐含意义为主语与at后所跟有宾语的接触为点接触，接触面小，多用于敲门）
打， 捶， 敲; 挝
Knock at my window at eight o'clock and I'll be ready.8点钟敲我的窗，我会准备好的。
2 Knock out淘汰; 击败; 出局; 使不省人事（out这里是副词，knock用作及物动词，直接接宾语，out用其本身意“出”）
This little lady will knock out a tank at 300 yards.这个小玩意能击毁300码远的坦克.
The boxer scored a knock out. 这位拳击手将敌手击昏得分.
3）Knock over偷窃; 碰翻; 使吃惊; 轻易击败（over有翻转过来之意）
The racoons knock over the rubbish bins in search of food, and strew the contents all over the ground.浣熊弄翻垃圾箱找吃的，把垃圾弄得满地都是。
Mike can knock over three or four of those simple drawings in a day. 迈克一天可完成三四张那样简单的图画.
Miss Ley trembled lest he should knock her china over as he went roundthe room.当他走进房间时,莱伊小姐害怕得打颤,唯恐他撞碎她的瓷器.
4）Knock off 使减少; 杀死; 下班; 偷（off本身有下降之意）
If I get this report finished I'll knock off early.如果我写完这篇报告，我就会早点下班。
When pressed they knock off 10 per cent.经砍价，他们降了10%。
标签：Knock,knock,out
