As we all know,the freight of the luggage is charged by weight.众所周知，行李的运费是按重量计算的。

3、by+交通工具、交通方式名词（名词前不加冠词，不变复数）。意为：“通过…，由…，乘…”。如by train/rail/tube/taxi/bus/truck/bike/boat/plane;by land/road/sea/water/air等。（on foot)

It takes a long time to go there by train;it`s quicker by road.(或by bus)(NMET93)乘火车去那儿要花很长时间，公路比较快。

“I usually go there by train”.“Why not try going by boat(或water)for a change?”(NMET92)“我常乘火车去那儿。”“为何不尝试一下坐船呢？”

4、by+抽象名词或具有抽象意义的普通名词（名词前不加冠词，不变复数）。意为：“靠…，通过…，由…所致”。如：by skill/determination/practice/diligence/inference/chance/accident;by mail/letter/radio/fax/telephone/telegraph/hand/machine等。

Although he had been searching in the wrong area most of the time,he found it by logic,not by luck.(NMET2002阅读）虽然他曾大部分时间一直在错误的地方寻找，但他还是靠逻辑推理而非运气，找到了它。

I made a coat with my own hands.It was made by hand,not by machine. 我用双手织了一件外套。它是用手工织的，而不是机器织的。

5、by+ 地点或工具等具体名词。表路线、途径，意为：“通过（某物、某地），取道…”。如:by a stone bridge/the back door/the freeway/country roads等。

The man entered the room by the back door.那人通过后门进入了房间。

6、by+动词—ing.意为：“通过…，靠…，凭…”。如：by aiting/practing/begging/working/imitating等。

He gained his wealth by printing works of famous writers.(NMET95)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. Similarly,our minds are developed by learning.(2000上海)身体是靠锻炼强壮的，同样，大脑是靠学习开发的

四、by+数量词。

1、表升降、增减的程度。如：by one-fifth/20 percent/￡3/two feet等。

With production up by 60%,the company has had another excellent year.(NMET2000)产量上升了百分之六十，这家公司今年的业绩极好。

The demand for organic food is increasing by about one third every year.(NMET2002阅读)对绿色食品的需求每年在增长大约三分之一。

2、表示距离和面积、体积中的尺寸及乘除法中的运算。如：by 2cm/6 inches/four feet/nine yards/a hair`s breadth等。

Luckily,the bullet narrowly missed the captain by an inch.(2002上海）幸运地是，那颗子弹差一英寸就击中了上尉。

The bed is three meters wide by two meters long,and can fit at least four at one time.(NMET2001阅读)那张床三米宽，两米长，一次至少可以睡四个人。

五、by+身体部位名词或衣服名词。表示被抓住身体/衣物的某一部分，常与动词catch/seize/take/hold/grab等连用。

如：by the hair/hand/arm/nose/horns;by the collar/lape/sleeve等。

The policeman caught the thief by the arm.警察抓住了小偷的胳膊。

The soldier grabbed the child by the collar.那个士兵揪住了孩子的衣领。

六、by的常见短语：

by means of/by way of/by the way/one by one/step by step/side by side/shoulder by shoulder/by oneself/by birth/by society/take…by 高中知识搜索小程序介词by可以用来表示方位、时间、手段等,其用法在高考中曾多次出现。下面结合高考试卷和其它一 surprise/learn…by heart/what do you mean by …/by my watch等。返回搜狐，查看更多