as什么情况下可以做主语?和it怎么区别?

as什么情况下可以做主语?和it怎么区别?
as什么情况下可以做主语?
和it怎么区别?

as什么情况下可以做主语?和it怎么区别?
貌似没见过
as
[As]
adv.
同样地, 被看作, 象
prep.
当做
conj.
与...一样, 当...之时, 象, 因为
[域] American Samoa, 东萨摩亚
abbr.
[军] Air to Surface, 空对地
As
symb 〈化〉砷 (arsenic)
AS
=Academy of Science科学院
as
as 1
AHD:[²z] […z ] 非重读时
D.J.[#z][*z ]非重读时
K.K.[#z][*z ]非重读时
adv.（副词）
To the same extent or degree; equally:
同等地,一样地：同一限度或程度地；同等地：
The child sang as sweetly as a nightingale.
这孩子歌唱得同夜莺般婉转
For instance:
例如：
large carnivores, as the bear or lion.
大的食肉动物,如熊或狮子
When taken into consideration in a specified relation or form:
被认为：当在特别的关系或形式中加以考虑时：
this definition as distinguished from the second one.
这个定义与第二个有区别
conj.（连接词）
To the same degree or quantity that. Often used as a correlative after so or as :
像,如同：同等的程度或量,常用作关联词后置于so 或 as ：
You are as sweet as sugar. The situation is not so bad as you suggest.
你甜如蜜.情形不如你说的那样糟
In the same manner or way that:
以同样方式,以同样方法：
Think as I think.
像我这样去想
At the same time that; while:
同时；当…时：
slipped on the ice as I ran home.
我跑回家时在冰上滑了一跤
For the reason that; because:
由于；因为：
went to bed early, as I was exhausted.
睡得早,因为我精疲力尽了
With the result that:
结果：
He was so foolish as to lie.
他太傻才会撒谎
Though:
尽管：
Great as the author was, he proved a bad model. Ridiculous as it seems, the tale is true.
这位作者尽管了不起,到头来却成了一个坏榜样.这个故事看似荒唐,却是真的
In accordance with which or with the way in which:
根据或按照这一方法：
The hotel is quite comfortable as such establishments go. The sun is hot, as everyone knows.
就设备而言,这个旅馆相当舒适.太阳非常热,这一点众所周知
Informal That:
【非正式用语】 相当于that：
I don't know as I can answer your question.
我不知道能否回答你的问题
pron.（代词）
That; which; who. Used after same or such :
that；which；who.用在same 或 such 后：
I received the same grade as you did.
我和你得分一样
Chiefly Upper Southern U.S. Who, whom, which, or that:
【多用于美国中南部】 who,whom,which或that：
Those as want to can come with me.
想去的可以和我同去
prep.（介词）
In the role, capacity, or function of:
以…的身份,作为：充当角色、身份或功能的：
acting as a mediator.
充当调解人
In a manner similar to; the same as:
以相似的方式；如同：
On this issue they thought as one.
在这个问题上,他们意见一致
as is【非正式用语】
Just the way it is, with no changes or modifications:
按现状：就用这种方式,不加改变或修饰：
bought the samovar as is from an antique dealer.
原封不动地从古董商那里买到这套俄国式茶具
as it were
In a manner of speaking; as if such were so.
以说的方式；似乎如此
Middle English
中古英语
from Old English ealsw³} * see also
源自 古英语 ealsw³} *参见 also
Traditionally, a distinction has been drawn between comparisons using as . . . as and comparisons using so . . . as. [x] The so . . . as construction is traditionally required in negative sentences ( as in Shakespeare's “ 'tis not so deep as a well” ), in questions (as in Is it so bad as she says? ), and in certain if clauses (as in If it is so bad as you say, you ought to leave ). But this so . . . as construction is becoming increasingly rare in American English, and the use of as . . . as is now entirely acceptable in all contexts. · In a comparison involving both as . . . as and than, [x] the second as should be retained in written style. One writes He 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. [x] This construction is not sufficiently well established to be used in writing. · [x]As should be preceded by a comma when it expresses a causal relation, as in She won't be coming, as we didn't invite her. [x] When used to express a time relation, as is not preceded by a comma:
按传统用法,用as…as 表比较和用 so…as 表比较二者有别. so…as 结构传统上用于否定句,（ 如莎士比亚“不如井深” ）, 和疑问句中（如在如她所说的那样糟糕吗? ）, 和某些if 从句中（如在 如果象你所说的那样糟,你就该离开 ）. 但so…as 结构在美国英语中日趋少见, 而在所有语境中使用as…as 现在则是完全可以接受的. 在有as…as 和 than 同时用作比较时, 在书面语中,第二个as 应该保留. 一种写法He is as smart as,or smarter than,his brother,（他如他兄弟一般聪明,甚至超过他了） ,而不应写成 He is as smart or smarter than his brother, 这在正式文件中被认为是不可接受的.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 . 这种结构在书面语中尚不成立.当as 表示一个因果关系时,前面应有逗号, 如She won't be coming, as we didn't invite her.（她不会来这里,因为我们没有邀请她） . 当用于表示时间关系时,as 前没有逗号：
She was finishing the painting as I walked into the room.[x]
She was finishing the painting as I walked into the room（我走进房间的时候她刚好画完画）.
When a clause introduced by as 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 sentence As 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, [x] as in They considered it as one of the landmark decisions of the civil rights movement. The measure was deemed as unnecessary.[x] This usage may have arisen by analogy to regard and esteem, [x] where as is standardly used in this way:
当as 引导一个从句且位于句首时,应注意弄清 as 是表示“原因”还是表示“与…同时”. 句子As they were leaving,I walked to the door 既可表示我向门口走去,因为他们离开了,也可表示在他们离开的时候,我向门口走去. as 有时赘用,引导动词的补助成分诸如 consider,deem, 和 account, . 如在他们将此认为是民权运动的里程碑. 认为此测量标准不必要. 这种用法也许源于词的类比用法regard 和 esteem , 在此as 这种形式的用法是标准的：
We regarded her as the best writer among us.[x]
我们认为她是我们中最好的作家.
But the use of as with verbs like consider is not sufficiently well established to be acceptable in writing. See Usage Note at because, equal, like 2so 1than
但在书面语中as 与动词连用象 consider 等尚不能完全被人们接受. 参见 because, equal, like2so1than
American dialects often vary from Standard English in the form and usage of relative pronouns. Where Standard English has three relative pronouns—who, which, and that —regional dialects, particularly those of the South and Midlands, allow as and what as relative pronouns: “Them as thinks they can whup me jest come ahead” (Publication of the American Dialect Society). The car what hit him never stopped.
美国的各种方言在关系代词的形式和用法上常与标准英语有出入.标准英语有三个关联代词who,which 和 that ——地区性方言, 尤其是南部和中部地区,却允许as 和 what 作关联代词： “Them as thinks they can whup me jest come ahead" （美国方言协会出版物）撞倒他的那辆车根本没停.
as
as 2
AHD:[²s]
D.J.[#s]
K.K.[#s]
n.（名词）
【复数】 as.ses[²s“¶z”, ²s“¹z]
An ancient Roman coin of copper or copper alloy.
阿斯：古罗马一种铜硬币或铜合金硬币
An ancient Roman unit o

同学，as 貌似不是名词，怎么会问这么奇怪的问题