by的后面要加动词的ing形式，因为是by是介词，介词后面要加名词、代词宾格或者动名词形式。by后面接动词的时候需要用动名词形式，即动词的ing形式，意思是“通过某种方式”。、

by的用法例句

by的后面加动词的ing形式

例句：He gained his wealth by printing works of famous writers.他通过印刷著名作家的作品而获得了巨大的财富。

Our bodies are strengthened by taking exercise. 我们的身体是靠锻炼强壮的。

He made a living by teaching.他以教书为生。

You can learning English by watching English movies.你可以通过看英语电影来学习英语。

by+交通工具，表示凭借、乘坐某种交通工具，在句中作方式状语

例句： She went to Beijing by air.她乘飞机去的北京。

I 'm going to Shanghai by train.我打算乘火车去上海。

They went to Qingdao by ship.他们坐轮船去的青岛。

by+地点名词.表方位，意为：“在…旁边”

They searched the top of the hill and stopped to rest on a big rock by the side of the path.他们搜索了山顶，然后停下来在路边的一块大石头上休息.

by+名词.可用来表方法、方式、手段等

Workers in big cities usually get paid by the hour.大城市里的工人通常按小时获得报酬。

by用于被动语态的句子中

He was praised by the teacher.他受到了老师的表扬。

The book was written by Xiaoming.这本书是小明写的。

by后面也可以接人称代词

例句：I learn English by myself.我自学英语。

by的例句

1. Doctors are complaining about being barraged by drug-company salesmen.

医生们抱怨他们疲于应付医药公司的销售人员。

2. He was hand-picked for this job by the Admiral.

他是由海军上将精心挑选出来担任这项工作的。

3. Barry had his nose put out of joint by Lucy's aloof sophistication.

露西的冷淡与世故使得巴里十分不快。

4. Nora was deflowered by a man who worked in a soda-water factory.

在汽水厂工作的一个男子夺去了诺拉的童贞。

5. You can improve your chances of profit by sensible planning.

你可以通过合理计划来提高盈利的机会。