我們先來看看一條在2014年由一個香港人發給MWALD的問題：
Question
Which preposition should I use in the sentence
"I work ___ a small company"? at? for? in? — V.
Chan, Hong Kong
我相信在香港這樣的問題是頗常見的，因為大家在日常工作中也有機會用到。我們看看Merriam
Webster的編輯怎樣答這問題：
Answer
In the
sentence "I work _____ a small company," you can use
either at or for.
"At a
small company" is the more common way to say this, but both
prepositions are absolutely fine and have almost exactly the same
meaning.
I think
that "for a small company" puts slightly more emphasis on
the fact that the speaker is an employee of a larger organization and not in
control of it. But the difference is slight, and I'm not sure
that all native speakers would agree with me.
問題答完了，但我這個帖子當然不會就這麼簡單就那同時完了。看完M-W編輯的答案，我現在有一個疑問她沒有解答到，而我亦相信很多香港人，甚至是台灣或大陸人，都有我同樣的疑問：就是為什麼不能用in？我絶對敢用自己的人頭去打賭，當說到在一間公司裡面工作，中國人第一句想到的英文必然是work in a
company，但M-W的編輯卻說應用for或at。那作為一個中國人，我們當然一定會問為何in不可以？如果你看下面從字典抽出來的例子：
She works
for an engineering company.(OALD)
He works for a company that
makes software. (CALD)
How many people work at your company? (Cambridge Business English Dictionary)
David works for a broadcasting
company. (Longman Business Dictionary)
那這個M-W的編輯又好像沒有說錯，那是不是因為名詞是company的關係呢？因為總覺得work
in a place是可以接受的。
在我即將面世論述有關各大學習型字典網站的文章中，朗文網站會是第一個出場的。我在當中提到朗文字典的一大優點是它有相對最多的usage notes在LDOCE內，這些資料在其他幾本字典都是很少的，MED在這方面應該是第二位。我們去到朗文網站的work條目的動詞部份看，你會見到有這樣的一段usage notes：
You work in a type of place such as a bank, shop, or
factory:
She
works in a library.
You work at a particular place or organization:
She
works at the Library of Congress.
You work for a person, company, or organization that
employs you:
He
works for his father.
We
both work for the same company.
上面的usage notes說明了什麼？我來解釋一下：
1. 當你說自己是「為某人，某公司或某機構工作」時，英文我們會說work for a company。所以香港讀者那條問題的答案是：I work for a small company，例如：
My brother works for a large American corporation.
(Cambridge Business English Dictionary)
She works for
a big law firm in the city. (MED)
He works for the U.S. Department of Transport.
(Cobuild)
我不敢說那個M-W的編輯是錯的，但如果是說一間公司，從上面的例子我們可以見到，我的首選會是work for
a company。
2. 如果你是要說「在某一種場所工作」時，如工廠，辦公室，醫院等，這時英文則會說work in a place，例如：
Most of the people I went to
school with work in factories. (Longman Business Dictionary)
I started working in a recording studio. (Cobuild)
I've never ever
worked in an office before, I've only ever worked as a waitress. (Oxford
Dictionary)
For years Paul had
worked in the hospitality business working mainly in bars that had loud music.
(Oxford Dictionary)
留意一點，如果你想說「在一間公司努力工作向上爬」，這時the company前面的介詞是in，它與短語work the way up連用：
work my way up in the company (Merriam Webster)
3. 而當你要說的是「某個特定的場所」，例如是浸會大學，而不是泛指在大學工作，這時你就要說work at a place，例如上面朗文的例句：
She
works at the Library of Congress.
這是國會裡面的圖書館，而不是普通的圖書館。
以上三點就是work後面接名詞地方時，前面應用什麼介系詞的基本原則。
M-W女編輯的解說雖然沒有錯，但不算十分到位。另外，有一個重點大家是要注意的，就是很多時work in和work at這二個用法，有時甚至是work for，都是可以互換的。在介詞中，for是解「為了」，所以你「替某人或某公司打工」，就是work for a
company/corporation etc. 。而介詞的at和in很多時都是「指一些physical
location」，所以就算不是指某些specific area，有時你也可用work at，例如：
1. He
works at the hospital.(CALD)
2. I work at the university. (LDOCE) [之前說過在學校之類的地方如university工作，一般只能用at，但有三個例外情況你可用in：school，kindergarten，college]
3. She works part-time at the restaurant. (MWALD)
4. he worked as a waiter in a rather shabby
restaurant (Oxford Dictionary)
現在我們來看一些字典中特殊例子：
1. I’ve
been working in
the garden all day. (MED)
2. She is working in the
garden. (MWALD)
3. Linda spends
all her time working on the garden. (Cobuild)
4. Neil
and Chris try to spend the minimum of time on the garden. (Cobuild corpus)
上面前二句例句是work in the garden，但後面二句例句卻是work on the garden。衆所週知，garden解作「花園」，「在花園中」的介詞片語我們一般會說in a garden，所以「在花園中工作」的英文很自然就是work in a/the
garden，但為什麼現在卻寫成了on the garden呢？可能有人會想，會不會是因為前面的動詞是spend，所以這句的句型變了spend time on sth呀？
這個想法不太正確。在一般字典中如朗文或麥美倫，英文中的spend可以有這二種句型：
spend time in a place或spend money on sth
但這些字典卻沒有spend time on sth這說法。這裏spend time和spend money後接不同的介系詞。不過，牛津高階現在收錄的句型數量應該早已超越了朗文當代，例如前者有provide sth to sb這句型，而後者則只有Business Dictionary有，旗艦字典LDOCE反而沒有，spend和provide的句型問題我在多年前的文章中已經分析過。而我在牛津也找到一個其他五本學習型字典都沒有收錄的句型，就是spend time on sth，例句：
How long did you spend on your homework? (OALD)
所以上面找到有關spend time (working) on the
garden的意思其實不是「（花時間）逗留在花園中」，而是「花時間在花園中進行某些跟花園有關的事/工作，例如維修裡面的設施或剪草等！」
跟著我們再看另一例句。這又是一句work on的例句，作者同樣沒有用in/at/for三個介系詞，這又是什麼原因？
She worked hard all
her life, rearing her family and working on the farm. (Oxford Dictionary)
這一句比較容易解釋，現今的英文，提到農場farm一字時，一般都會說on a farm，而不是in a farm，這幾乎是最常見的用法。除了on a farm外，有時你也可用at a farm，但這用法如今應該比較少見。老一輩的語法專家Frederick T. Wood在其名著中就說過：
"A farm-worker, or anyone engaged either
permanently or temporarily in agricultural work, works on a farm:
e.g. During the university vacation he worked on a
farm
but someone who is doing work not connected with
farming, but on the farm premises, works at a farm (e.g. a person doing domestic work, a
builder building or repairing outhouses).
Even for farm-workers, at is used if a particular farm is specified:
e.g. He works at Blackmoor Farm.
e.g. This is the farm at which I used to work
(cf. work in a
factory, but work at a
particular factory that is named.)"
[English Prepositional Idioms, 1967]
留意Frederick T. Wood最後說的那一句正好呼應朗文前面提到的語法規則，in用在一般場所上，而at則指某些特定場所。
總結：如果要說在某地方工作，我們有多個介系詞可選用，它們的意思稍有不同，視乎你要說的context。其實，除了這意思外，work在其它用法上也會配不同介詞或句型，這時你便要靈活運用，才不致寫錯英文。多看英文報章雜誌小說，可令你寫的英文更加地道，當然你也可以懶一點，單看字典中的例句也可以。所以我經常強調句型和介詞的重要性。要寫idiomatic或natural English，你必需要熟知這每個字的相關句型的和相連介詞，否則你寫的英文只是文法正確，但不合慣用法的「中式英文」，看上去總給人怪怪的感覺！
