by用法归纳口诀

　　另外by的用法还有以下几种：

　　一、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.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。

　　二、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.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)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?”“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。

　　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 waiting/practing/begging/working/imitating等。

　　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。

　　三、by+数量词。

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

　　The demand for organic food is increasing by about one third every year.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.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.那张床三米宽，两米长，一次至少可以睡四个人。

　　四、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。