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些例句做一下归纳：
一、by+地点名词。表方位，意为：“在…旁边”。如： by the lake/river/tree/window/door等。
She searched the top of the hill and stopped to rest on a big rock by the side of the path.(NMET90)她搜索了山顶，然后停下来在路边的一块大石头上休息。
After supper she would sit down by the fire,sometimes for as long as an hour,thinking of her young and happy days.(2003上海·春）晚饭后，她常坐在火旁，有时长达一个小时地回忆她那青春、快乐的年代。
注：有时可表:“从…旁经过”,多与动词go/walk/pass等连用。
As we boys were rushing towards the playground,Jim slipped by the table.(NMET92完形）当我们这些男生冲向操场时，吉姆从桌旁溜过。
二、by+时间名词。意为：“到…时（已发生某事），此时谓语多用完成时；最晚、不迟于…，在…之前”。
如：by now/then/this time/next Friday/the end of/three o`clock等。
By the end of last year,another new gymnasium had been completed.(2003上海·春）到去年年底，又有一座新体育馆峻工了。
The train leaves at 6:00 pm.So I have to be at the station by 5:40 pm at the latest.(NMET97)火车下午六点开，所以最晚我得五点四十赶到车站。
三、by+名词。可用来表方法、方式、手段等。
1、by+the+可数的时间、长度、重量等名词。意为：“按…计算，按…买(卖)”。如：by the pound/ton/yard/meter/dozen/bale/day/month等。
Cleaning women in big cities usually get paid by the hour.(NMET98)城市里的女清洁工通常按小时获得报酬。
In the market,tobacco is sold by the bale,eggs by the dozen and salt by the pound.在市场里，烟叶按捆卖，鸡蛋按打卖，盐按磅卖。
2、by+表示时间、长度、重量等总称的不可数名词（名词前不加冠词）。意为：“按…计算，按…买(卖)”。如：by time/volume/length/weight/height/depth/width/area等。
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。
