【1】knock sb/sth down=knock down sb/sth=sb/sth be knocked down

(1)vt.被车撞倒

He died in hospital after being knocked down by a car.  

他被车撞倒后死在了医院。

A drunk driver knocked down and killed two girls.  

一个酒后驾驶的司机撞死了两个女孩儿。

(2)vt.推倒，拆掉，拆毁（建筑物）

Why doesn't he just knock the wall down?.  

他为何不干脆把墙推倒？

They have since knocked down the shack.  

从那以后他们拆掉了简陋的棚屋。

(3)vt.降（价）；杀（价）；减（量）

The market might abandon the stock, and knock down its price.

市场可能会抛售该股票，从而令其股价下跌。

It manages to knock rents down to $1 per square foot.  

成功地将租金降到每平方英尺1美元。

【2】knock over 碰翻；弄翻，打翻

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。

The cat couldn't possibly knock over the trash can.  

猫不会把垃圾桶拱翻.

Try not to knock that vase over.  

小心别把花瓶碰倒了。

Look out! Don't knock the stool over.  

哎,别把凳子碰倒了!

【3】knock out

(1) vt.使不省人事；使入睡 

He was arguing with his girlfriend and she hit him with a frying pan! Nearly knocked him out.  

他和女友争吵时女友竟拿煎锅砸他！几乎把他砸晕了过去。

The three drinks knocked him out. 

3杯酒就让他昏昏入睡了。

(2)vt.击败；淘汰

Henri Leconte has been knocked out in the quarter-finals of the Geneva Open. 

亨利·勒孔特在日内瓦公开赛四分之一决赛中被淘汰。

The Irish came so close to knocking England out of the European Championships. 

爱尔兰队险些将英格兰队从欧锦赛中淘汰出局。

(3)vt.摧毁；使瘫痪

Our bombers have knocked out the mobile launchers.  

我们的轰炸机摧毁了移动火箭发射台。

A storm has made roads treacherous and knocked out power.  

一场暴风雨致使公路隐患重重且电力瘫痪。

【1】be dressed as 为dress sb as被动语态结构

结构:主语+be dressed as+宾语,意思为"主语被打扮成XXX"

They were all dressed as clowns.  

他们都打扮成小丑。

I was dressed as a horseman at the ball.  

在舞会上我装扮成骑士.

【1】dress up as为一个短语动词  意思为“装扮成，打扮成；假扮；扮作”

结构：主语+dress up as +宾语，主语打扮成为XXX"

Little girls dress up as angels for fiestas.  

小女孩们在节日里扮成天使的样子。

The children thought it great sport to dress up as pirates.  

孩子们觉得装扮成海盗很好玩.

They have organized games and the staff dress up as clown.  

他们组织各种游戏,所有人都装扮成小丑.

备注：be dressed as , dress up as 中的as的都是介词词性