1. by accident [偶然；意外地]
[构成]:by[通过] + accident[事故；意外]
例句：I met her by accident at the supermarket. [我在超市偶然遇见了她。]

2. by air [乘飞机]
[构成]:by[通过] + air[空气；天空]
例句：They traveled by air. [他们乘飞机旅行。]

3. by bike [骑自行车]
[构成]:by[通过] + bike[自行车]
例句：He goes to school by bike. [他骑自行车去上学。]

4. by bus [乘公共汽车]
[构成]:by[通过] + bus[公共汽车]
例句：I usually go to work by bus. [我通常乘公共汽车去上班。]

5. by chance [碰巧；偶然]
[构成]:by[通过] + chance[机会；偶然]
例句：I found the book by chance. [我偶然发现了这本书。]

6. by oneself [独自；单独]
[构成]:by[通过] + oneself[自己]
例句：She did the homework by herself. [她自己做的作业。]

7. by the way [顺便说；顺便问一下]
[构成]:by[通过] + the[定冠词] + way[道路；方法]
例句：By the way, how are you? [顺便问一下，你好吗？]

8. by means of [用；依靠]
[构成]:by[通过] + means[方法；手段] + of[关于]
例句：He succeeded by means of hard work. [他依靠努力工作成功了。]

9. by far [到目前为止；...得多]
[构成]:by[通过] + far[远]
例句：This is by far the best book I've read. [这是到目前为止我读过的最好的书。]

10. step by step [逐步地；一步一步地]
[构成]:step[步骤；脚步] + by[通过] + step[步骤；脚步]
例句：We should solve the problem step by step. [我们应该逐步解决这个问题。]

11. one by one [一个接一个地]
[构成]:one[一个] + by[通过] + one[一个]
例句：The students came in one by one. [学生们一个接一个地进来。]

12. side by side [并肩；一起]
[构成]:side[边；侧面] + by[通过] + side[边；侧面]
例句：They walked side by side. [他们并肩走着。]

13. little by little [逐渐地；一点一点地]
[构成]:little[小的；少的] + by[通过] + little[小的；少的]
例句：The fog cleared little by little. [雾逐渐散去了。]

14. day by day [一天天；逐日]
[构成]:day[天] + by[通过] + day[天]
例句：Her health is improving day by day. [她的健康状况一天天在好转。]

15. year by year [逐年；一年一年地]
[构成]:year[年] + by[通过] + year[年]
例句：The tree grows taller year by year. [这棵树逐年长高。]

16. by the end of [到...结束时；在...尽头]
[构成]:by[通过] + the[定冠词] + end[结束；末端] + of[关于]
例句：We'll finish the work by the end of this month. [我们将在本月底完成这项工作。]

17. by and by [不久；很快]
[构成]:by[通过] + and[和] + by[通过]
例句：He'll come back by and by. [他很快就会回来。]

18. by hand [用手；手工]
[构成]:by[通过] + hand[手]
例句：The sweater was made by hand. [这件毛衣是手工织的。]

19. by mistake [错误地；无意中]
[构成]:by[通过] + mistake[错误]
例句：I took your bag by mistake. [我错拿了你的包。]

20. pass by [经过；路过]
[构成]:pass[通过；经过] + by[通过]
例句：A car passed by just now. [刚才一辆车经过了。]