1. down and out [穷困潦倒；一无所有]
[构成]：down[向下；沮丧] + and[和] + out[出去；外面]
例句：After the business failure, he was down and out. [生意失败后，他变得穷困潦倒。]

2. down the drain [浪费；白费；化为乌有]
[构成]：down[向下] + the[定冠词] + drain[排水；消耗]
例句：All his efforts went down the drain. [他所有的努力都白费了。]

3. down in the dumps [心情低落；沮丧]
[构成]：down[向下] + in[在...里面] + the[定冠词] + dumps[垃圾场；忧郁]
例句：She's been down in the dumps since she lost her job. [自从丢了工作，她一直情绪低落。]

4. down to earth [实际的；务实的]
[构成]：down[向下] + to[到] + earth[地球；地面]
例句：He's a very down-to-earth person. [他是个非常务实的人。]

5. down payment [预付款；定金]
[构成]：down[向下] + payment[付款；支付]
例句：You need to make a down payment to buy this house. [买这房子你得先付定金。]

6. break down [分解；发生故障；失败]
[构成]：break[打破；弄坏] + down[向下]
例句：The machine broke down. [机器出故障了。]

7. calm down [平静下来；镇定下来]
[构成]：calm[平静的；使平静] + down[向下]
例句：Calm down and tell me what happened. [冷静下来，告诉我发生了什么。]

8. close down [关闭；停业]
[构成]：close[关闭；结束] + down[向下]
例句：The factory had to close down due to financial problems. [由于财务问题，工厂不得不关闭。]

9. cut down [削减；砍倒]
[构成]：cut[切；割] + down[向下]
例句：We should cut down on our expenses. [我们应该削减开支。]

10. fall down [跌倒；失败]
[构成]：fall[落下；跌倒] + down[向下]
例句：She fell down and hurt her knee. [她跌倒了，伤了膝盖。]

11. get down [下来；使沮丧]
[构成]：get[得到；变得] + down[向下]
例句：Get down from the tree. [从树上下来。]

12. hand down [传下来；宣布]
[构成]：hand[手；传递] + down[向下]
例句：This tradition has been handed down for generations. [这个传统已经传承了好几代。]

13. lie down [躺下]
[构成]：lie[躺；位于] + down[向下]
例句：You look tired. You should lie down and rest. [你看起来很累，应该躺下休息。]

14. look down on [轻视；看不起]
[构成]：look[看] + down[向下] + on[在...上面]
例句：Don't look down on others just because they are poor. [不要因为别人穷就看不起他们。]

15. put down [放下；镇压；贬低]
[构成]：put[放；安置] + down[向下]
例句：Put down your bag and sit here. [放下你的包，坐这儿。]

16. set down [写下；记下]
[构成]：set[放置；设定] + down[向下]
例句：Set down your ideas before you forget them. [在忘记之前把你的想法写下来。]

17. slow down [减速；放慢]
[构成]：slow[慢的；放慢] + down[向下]
例句：You need to slow down when you drive in the rain. [下雨天开车你得减速。]

18. turn down [拒绝；关小；调低]
[构成]：turn[转动；转向] + down[向下]
例句：He turned down my invitation. [他拒绝了我的邀请。]

19. write down [写下；记录]
[构成]：write[写] + down[向下]
例句：Write down your name and address. [写下你的姓名和地址。]

20. take down [取下；拆卸；记录]
[构成]：take[拿；取] + down[向下]
例句：Take down the picture from the wall. [把墙上的画取下来。]