1．by
（1）表示方法,手段.即“用.,通過.”相當(dāng)于by means of 如：
All work had to be done by hand 所有的工作都是手工進(jìn)行的.
He makes a living by teaching 他以教書為生.
（2）表示傳達(dá)、傳遞的方式或煤介.如：
How did you send the letter,by airmail or by ordinary mail?
你是怎么發(fā)送的這信,是通過航天郵件還是普通郵件?
（3）表示用交通工具、通訊工具后接名詞單數(shù),不加冠詞.如：
He came by train,but his wife came by bus.他是乘火車來的,可是他老婆是坐公共汽車來的.
注意下面兩句的區(qū)別：
Did you come by train?=Did you come in his car / on my bike?
“by +抽象名詞”構(gòu)成的詞組有：by accident / by chance / by diligence / by effort / by force / by heart / by luck / by mistake / by hard work.
（4）指數(shù)量增加或減少到的程度,相差.
We lost the match by one goal 我們僅以一球之差輸了比賽.
（5）根據(jù),按照
pay sb by the hour /day/week
Sell sth by the pound /meter/ dozen
sell sth by weight/length
As a rule,domestic servants doing odd jobs are paid by the hour 通常,家政服務(wù)是按照小時(shí)計(jì)酬的.
2.through
（1） 表示“以；通過；經(jīng)由”.如：
He succeeded through hard work.
（2） 空間上通過,透過,經(jīng)過
Light comes in through the window.光線從窗戶進(jìn)來.
（3） 時(shí)間上通過,自始至終,從頭到尾經(jīng)過
He often works through the night 他常常通宵工作.
注意：在表示手段時(shí),by,through有時(shí)也可換用.如：
Through / By his efforts he succeeded in making so many useful inventions.