as, because, for, since

as, like

though, although, as, even though

• he will not tell the secret even though（even if）he knows it．
  即使他知道這個(gè)秘密，他也不肯說出來。
• he will not tell the secret though he knows it．
  他雖然知道這個(gè)秘密，但他不會(huì)說出來。

when, while, as

名詞 as:

1. a very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and various alloys; found in arsenopyrite and orpiment and realgar
   同義詞：arsenic, atomic number 33
2. a United States territory on the eastern part of the island of Samoa
   同義詞：American Samoa, Eastern Samoa

副詞 as:

1. to the same degree (often followed by `as')
   同義詞：equally, every bit

1. Cyprus, as you know, is an island in the Mediterranean.
   如你所知，塞浦路斯是地中海的島國(guó)。
2. As if unsure of where she was, she hesitated and looked round.
   她彷佛茫然不知身在何處，猶猶豫豫向四周打量。
3. As she's been ill perhaps she'll need some help.
   她由於生病可能需要些幫助。
4. As you weren't there I left a message.
   因?yàn)槟悴辉谀抢?，我留了個(gè)信兒。
5. Jim runs fast, but I run just as fast.
   吉姆跑得快，但我跑得也一樣快。
6. The kitten uses that box as its bed.
   小貓把那個(gè)盒子當(dāng)做它的床。
7. He can run as fast as I can.
   他能跑得和我一樣快。
8. It is just as you like.
   事情就如你喜歡的那樣。

as

adv.（副詞）
To the same extent or degree; equally:
同等地，一樣地：同一限度或程度地；同等地：
例句：
The child sang as sweetly as a nightingale.
這孩子歌唱得同夜鶯般婉轉(zhuǎn)

For instance:
例如：
例句：
large carnivores, as the bear or lion.
大的食肉動(dòng)物，如熊或獅子

When taken into consideration in a specified relation or form:
被認(rèn)為：當(dāng)在特別的關(guān)系或形式中加以考慮時(shí)：
例句：
this definition as distinguished from the second one.
這個(gè)定義與第二個(gè)有區(qū)別

conj.（連接詞）
To the same degree or quantity that. Often used as a correlative afterso or as :
像，如同：同等的程度或量，常用作關(guān)聯(lián)詞后置于so 或 as ：
例句：
You are as sweet as sugar. The situation is not so bad as you suggest.
你甜如蜜。情形不如你說的那樣糟

In the same manner or way that:
以同樣方式，以同樣方法：
例句：
Think as I think.
像我這樣去想

At the same time that; while:
同時(shí)；當(dāng)…時(shí)：
例句：
slipped on the ice as I ran home.
我跑回家時(shí)在冰上滑了一跤

For the reason that; because:
由于；因?yàn)椋?/br>例句：
went to bed early, as I was exhausted.
睡得早，因?yàn)槲揖ＡΡM了

With the result that:
結(jié)果：
例句：
He was so foolish as to lie.
他太傻才會(huì)撒謊

Though:
盡管：
例句：
Great as the author was, he proved a bad model. Ridiculous as it seems, the tale is true.
這位作者盡管了不起，到頭來卻成了一個(gè)壞榜樣。這個(gè)故事看似荒唐，卻是真的

In accordance with which or with the way in which:
根據(jù)或按照這一方法：
例句：
The hotel is quite comfortable as such establishments go. The sun is hot, as everyone knows.
就設(shè)備而言，這個(gè)旅館相當(dāng)舒適。太陽(yáng)非常熱，這一點(diǎn)眾所周知

Informal That:
【非正式用語(yǔ)】 相當(dāng)于that：
例句：
I don`t know as I can answer your question.
我不知道能否回答你的問題

pron.（代詞）
That; which; who. Used aftersame or such :
that；which；who。用在same 或 such 后：
例句：
I received the same grade as you did.
我和你得分一樣

Chiefly Upper Southern U.S. Who, whom, which, or that:
【多用于美國(guó)中南部】 who，whom，which或that：
例句：
Those as want to can come with me.
想去的可以和我同去

prep.（介詞）
In the role, capacity, or function of:
以…的身份，作為：充當(dāng)角色、身份或功能的：
例句：
acting as a mediator.
充當(dāng)調(diào)解人

In a manner similar to; the same as:
以相似的方式；如同：
例句：
On this issue they thought as one.
在這個(gè)問題上，他們意見一致

<習(xí)慣用語(yǔ)>as is【非正式用語(yǔ)】
Just the way it is, with no changes or modifications:
按現(xiàn)狀：就用這種方式，不加改變或修飾：
例句：
bought the samovar as is from an antique dealer.
原封不動(dòng)地從古董商那里買到這套俄國(guó)式茶具

as it were
In a manner of speaking; as if such were so.
以說的方式；似乎如此
來源：
Middle English
中古英語(yǔ)
from Old English ealsw3 * see also
源自 古英語(yǔ) ealsw3 *參見 also

Traditionally, a distinction has been drawn between comparisons usingas . . . as and comparisons using so . . . as. Theso . . . as construction is traditionally required in negative sentences ( as in Shakespeare`s. `tis not so deep as a well. ), in questions (as inIs it so bad as she saysô ), and in certainif clauses (as in If it is so bad as you say, you ought to leave ). But thisso . . . as construction is becoming increasingly rare in American English, and the use ofas . . . as is now entirely acceptable in all contexts. · In a comparison involving bothas . . . as and than, the secondas should be retained in written style. One writesHe is as smart as, or smarter than, his brother, not He is as smart or smarter than his brother, which is considered unacceptable in formal style. ·In many dialects,as is used in place of that in sentences like We are not sure as we want to go or It`s not certain as he left. This construction is not sufficiently well established to be used in writing. ·As should be preceded by a comma when it expresses a causal relation, as inShe won`t be coming, as we didn`t invite her. When used to express a time relation,as is not preceded by a comma:
按傳統(tǒng)用法，用as…as 表比較和用 so…as 表比較二者有別。 so…as 結(jié)構(gòu)傳統(tǒng)上用于否定句，（ 如莎士比亞.不如井深. ）， 和疑問句中（如在如她所說的那樣糟糕嗎ô ）， 和某些if 從句中（如在 如果象你所說的那樣糟，你就該離開 ）。 但so…as 結(jié)構(gòu)在美國(guó)英語(yǔ)中日趨少見， 而在所有語(yǔ)境中使用as…as 現(xiàn)在則是完全可以接受的。 在有as…as 和 than 同時(shí)用作比較時(shí)， 在書面語(yǔ)中，第二個(gè)as 應(yīng)該保留。 一種寫法He is as smart as，or smarter than，his brother，（他如他兄弟一般聰明，甚至超過他了） ，而不應(yīng)寫成 He is as smart or smarter than his brother， 這在正式文件中被認(rèn)為是不可接受的。在很多方言中，用as 代替 that 如 We are not sure as we want to go 或 It`s not certain as he left 。 這種結(jié)構(gòu)在書面語(yǔ)中尚不成立。當(dāng)as 表示一個(gè)因果關(guān)系時(shí)，前面應(yīng)有逗號(hào)， 如She won`t be coming, as we didn`t invite her。（她不會(huì)來這里，因?yàn)槲覀儧]有邀請(qǐng)她） 。 當(dāng)用于表示時(shí)間關(guān)系時(shí)，as 前沒有逗號(hào)：
例句：
She was finishing the painting as I walked into the room.
She was finishing the painting as I walked into the room（我走進(jìn)房間的時(shí)候她剛好畫完畫）。

When a clause introduced byas begins a sentence, care should be taken that it is clear whether as is used to mean .because. or .at the same time as.. The sentenceAs they were leaving, I walked to the door may mean either that I walked to the door because they left or at the same time that they were leaving. · As is sometimes used superfluously to introduce the complements of verbs like consider, deem, and account, as inThey considered it as one of the landmark decisions of the civil rights movement. The measure was deemed as unnecessary. This usage may have arisen by analogy toregard and esteem, whereas is standardly used in this way:
當(dāng)as 引導(dǎo)一個(gè)從句且位于句首時(shí)，應(yīng)注意弄清 as 是表示.原因.還是表示.與…同時(shí).。 句子As they were leaving，I walked to the door 既可表示我向門口走去，因?yàn)樗麄冸x開了，也可表示在他們離開的時(shí)候，我向門口走去。 as 有時(shí)贅用，引導(dǎo)動(dòng)詞的補(bǔ)助成分諸如 consider,deem， 和 account， 。 如在他們將此認(rèn)為是民權(quán)運(yùn)動(dòng)的里程碑。 認(rèn)為此測(cè)量標(biāo)準(zhǔn)不必要。 這種用法也許源于詞的類比用法regard 和 esteem ， 在此as 這種形式的用法是標(biāo)準(zhǔn)的：
例句：
We regarded her as the best writer among us.
我們認(rèn)為她是我們中最好的作家。

But the use ofas with verbs like consider is not sufficiently well established to be acceptable in writing. See Usage Note at because ,equal ,like 2so than
但在書面語(yǔ)中as 與動(dòng)詞連用象 consider 等尚不能完全被人們接受。 參見 because,equal,like2sothan

as
as 2

n.（名詞）
【復(fù)數(shù)】 as.ses[2s.ôz., 2s.z]
An ancient Roman coin of copper or copper alloy.
阿斯：古羅馬一種銅硬幣或銅合金硬幣
An ancient Roman unit of weight equal to about one troy pound.
阿斯：古羅馬一種重量單位，約金衡制一磅

來源：
Latin 3s
拉丁語(yǔ) 3s