China is a developing country,______ is known to all. 

答案填 which 和as 有什么不同？必须填 as 么？which 我觉得也可以。

翻译成：中国是个发展中国家，这一点众所周知。

这没什么问题吧？谢谢！

解答：

从句位于主句之后时，as和which都可以。但意思有细微差别。as即使引导定语从句，也多少带有同级比较的意味。隐含的意思是，“一加一等于二”等常识是大家都知道的。大家知道“中国是发展中国家”就像大家知道“一加一等于二”等常识一样。所以常用在显而易见的场合。字面的意思是：“正如大家知道的那样。”（虽然已经有了套语“众所周知”。）如果用which,就没有了比较的意味，仅仅是“这一点大家都知道”。这种细微的差异常被人们忽略。所以，在主句之后时，as和which都可以用，差别可以忽略。

但从句如果在主句之间，则只能用as，不能用which了。

China is a developing country,______ is known to all.

答案填 which 和as 有什么不同？必须填 as 么？which 我觉得也可以。

翻译成：中国是个发展中国家，这一点众所周知。

这没什么问题吧？谢谢！

解答如下：

以上关系代词as,which,都可以，但是他们略有区别

as与 which引导非限制性定语从句的区别

(1)as 引导的从句表示说话人的态度，看法，解释或者评论

 as 引导非限制性定语从句常作行为动词see, know, hear, watch, remember, say, tell, show, expect, guess的宾语，可以放在句首，句中，句末，翻译为正如/正像)

引导先行词是整个主句内容的非限制性定语从句.

As 可引导的先行词是整个主句内容的非限制性定语从句,在句中作主语,宾语.它引导的从句可以位于主句前,也可以位于主句后,还可以位于主从句中间

A:位于主句之后

Tom is a brave boy, as is described in the report.

汤姆是一个勇敢的男孩，这正如在报道中描述的那样。

（从句在主句之后，as作从句的主语）

He is a great hero, as is described in the report.

正如报道中描述的那样,他是个伟大英雄.

She is a famous film star, as we all know.

正如我们都知道的,她是一个著名电影明星.

She is very patient , as is shown in her work.

She has been absent again, as is expected.

There is a net bar around here, as I remember.

我记得这儿附近有一家网吧。

B.位于主句之前(从句在主句之前，as作从句的宾语）

As everybody knows, Shakespeare was a great English writer.

众所周知，莎士比亚是伟大的英国作家。

As we had expected, the plan worked out very well.

正如我们预料的,这个计划运行的非常好.

As everybody knows, Shakespeare is a famous writer.

正如每个人/大家都知道，莎士比亚是一个著名作家.

As is known to everybody, the moon travels around the earth once every month.

=The moon travels around the earth once every month , as is known to everybody.

As is often the case, girls like dolls while boys like guns.

女孩子喜欢玩具而男孩子喜欢枪，这是常见的情况。

As is often the case, little boys tend to be very active and out of control.

Einstein, as we know, is a famous scientist.

As has been mentioned above, computers have many advantages .

Great changes have taken place inChina, as is known to all.

There was a net bar around there, as I remember .

C.位于主句与从句之间(从句在主句中间，as作从句的宾语）

She ,as we all know, can speak three foreign languages.

正如我们都知道的那样,她会说3门外语.

 The project, as we had expected, got along well.

正如我们所预料的那样，工程进展顺利。

The famous magician Liu Qian, as we all know, is fromTaiwan.

众所周知，著名魔术师刘谦是台湾人。

D.as 代替前面主句整句话内容，通常用于以下【几种固定表达结构】

as引导非限制性定语从句时，常见的【固定表达】

as anybody can see 正如人人都能看见的那样

As is well known=as is known to all 众所周知

As we (have) expected 正如我们所预料的

As is often the case 正如往常那样/这是常有的事情

As has been said before 正如前面所说的

As is mentioned above 正如上面提到的

As I remember 正如我所记得的那样

as we all know众所周知  

as I can remember正如我所记得的

as often happens像经常发生的那样

as we expect正如我们预料的那样

as you see这一点你明白

as was expected正如预料的那样

as can be seen看得出来

 as may be imagined正如可以想象的那样

as has been said above 如上所述

 as we all can see 正如我们都能看到的那样

as is often the case 像常规那样

as everybody can do 正如人人都能做到的那样

(1)which 引导的从句对主句所叙述的事情进行补充，表示会导致某种状态或结果.（表示，这一点，这件事情；与主句有种因果，并列关系放在主句之后，用逗号隔开.）

He changed his mind again, which made us all angry.

他又改变了主意，这使我们大家都生气了。

She tore up my photos, which (=and that) upset me.

她撕碎了我的照片，这使我很不安。

She stole her friend’s money, which(=and that) was disgraceful.

He tore up my photo, which(=and that) upset me.

He has passed the College Entrance Examination, which makes his parents quite happy.

(2)在从句中作定语或者介词的宾语，需要用which

Jenny might come, in which case I'll ask her.

詹妮可能会来，要是那样的话我就去问她。

She graduated from a local middle school, after which she went to Beijing  University.

她毕业于当地的一所中学，之后她去了北京大学。

He was educated at the local grammar school , after which he went on to Cambridge.

Lily might possibly come, in which case I will ask her .

(3)不能省略非限制性定语从句的be 时，用which，反之用as

Jane told me she won the match, which was a lie.(不能省略）

As(was) planned, we met at the airport.(可省略助动词be)

(4)当从句是否定句或者从句谓语动词跟复合宾语时，一般用which不用as

He pretended not to know me, which I didn’t understand .

He admires everyone in the class, which I find quite strange

(5)当从句的谓语动词是否定形式或含着一个复合宾语时，一般用which而不用as。

He pretended not to know me, which I didn't understand.

他假装不认识我，这是我搞不明白的。

He admires everyone in his class, which I find quite strange.

他羡慕班里的每个学生，我认为太奇怪了。