1. drop by [顺便拜访]
[构成]：drop[落下；降低] + by[在...旁边]
例句：Drop by anytime. [随时过来坐坐。]

2. drop in [顺便走访；偶然拜访]
[构成]：drop[落下；降低] + in[在...里面]
例句：Why don't you drop in for a drink? [你为什么不顺便进来喝一杯？]

3. drop off [减少；让...下车；睡着]
[构成]：drop[落下；降低] + off[离开；脱落]
例句：Business has dropped off recently. [近来生意清淡了。]

4. drop out [退学；退出；脱离]
[构成]：drop[落下；降低] + out[出去；离开]
例句：He dropped out of college. [他从大学退学了。]

5. drop behind [落后；落伍]
[构成]：drop[落下；降低] + behind[在...后面]
例句：Don't drop behind in your studies. [学习上别落后。]

6. drop away [逐渐减少；减弱]
[构成]：drop[落下；降低] + away[离开；消失]
例句：The crowd dropped away as the night wore on. [随着夜幕降临，人群逐渐散去。]

7. drop back [退后；落后]
[构成]：drop[落下；降低] + back[向后；后面]
例句：The runner dropped back at the last lap. [那个赛跑选手在最后一圈落后了。]

8. drop down [突然倒下；顺着向下移动]
[构成]：drop[落下；降低] + down[向下]
例句：The bird dropped down to the ground. [鸟儿突然落到地上。]

9. drop in on [顺道拜访]
[构成]：drop[落下；降低] + in[在...里面] + on[在...上面]
例句：Drop in on me when you have time. [有时间来看看我。]

10. drop out of [从...中退出]
[构成]：drop[落下；降低] + out[出去；离开] + of[关于；属于]
例句：She dropped out of the race. [她退出了比赛。]

11. eye drop [眼药水]
[构成]：eye[眼睛] + drop[滴；落下]
例句：Use eye drops to relieve eye fatigue. [用眼药水缓解眼睛疲劳。]

12. water drop [水滴]
[构成]：water[水] + drop[滴；落下]
例句：The water drop fell from the leaf. [水滴从叶子上落下。]

13. a drop of [一滴...]
[构成]：a[一个] + drop[滴；落下] + of[关于；属于]
例句：A drop of blood fell on the floor. [一滴血滴在了地板上。]

14. temperature drop [温度下降]
[构成]：temperature[温度] + drop[下降；降低]
例句：There was a significant temperature drop last night. [昨晚气温大幅下降。]

15. pressure drop [压力下降]
[构成]：pressure[压力] + drop[下降；降低]
例句：The pressure drop in the pipeline needs to be monitored. [管道中的压力下降需要被监测。]

16. price drop [价格下降]
[构成]：price[价格] + drop[下降；降低]
例句：The price drop of this product attracts many customers. [这个产品的价格下降吸引了很多顾客。]

17. drop zone [空投区；降落区]
[构成]：drop[落下；空投] + zone[区域；地带]
例句：The paratroopers landed in the designated drop zone. [伞兵在指定的空投区着陆。]

18. drop curtain [垂幕；幕布]
[构成]：drop[落下；垂下] + curtain[窗帘；幕布]
例句：The drop curtain was lowered at the end of the performance. [演出结束时幕布降下。]

19. drop shipment [直接发货；直运]
[构成]：drop[落下；发送] + shipment[装货；运输]
例句：We offer drop shipment service for our customers. [我们为客户提供直接发货服务。]

20. drop handlebars [下弯式车把]
[构成]：drop[落下；降低] + handlebars[车把]
例句：The bike has drop handlebars for a more aerodynamic position. [这辆自行车有下弯式车把，以获得更符合空气动力学的位置。]