Question

as it is known to all (that...) (as 做状语从 句连词，是状语从

as it is known to all (that...) (as 做状语从 句连词，是状语从句, 可以加that)～这里为什么可以加that？如果加了that，后面不也是从句吗～就没有主句了啊～

Answer 1

1.你的题目有点问题，应该是混合了as is known to all,……句型和It is known to all that……句型。
1）前者as is known to all作状语，后面是跟一个完整句子的，例如：:As is known to all,the earth is round. 整个去掉也成立。 后面一句是主句；也可以是As is known to all that the earth is round.你看哪一部分是句子的主体。
2）后者一个是形式主语It引导的同位语从句，that引导从句。真正的主语是the earth..It is known to all that the earth is round. 真正的主语是后面的从句。前面一部分是主句。
希望帮到你~

Answer 2

同位语从句

追答

That不能省略 that解释前面的it

追问

可是这样句子就只有同位从和as引导的壮从～句子中没有主语～

Answer 3

As is known to all that the earth is round, 你采纳的回答中这个句子是错的！

1. 如果as引导定语从句，as作定语从句的主语，没有it，更没有that。整个句子是：As is known to all, the earth is round. 你不妨记一记这几个常用表达：as is mentioned above, as has been said above, as is often the case.

2. 如果没有is，则是“as+过去分词”作状语的用法，即as known to all作状语。没有it，更没有that。

3. 如果不去掉that，如你所说，that又引导了一个从句，也就是这种“过去分词作状语”的情况，往往可以化作从句，此句即：As it is known to all that the earth is round, you shouldn't make such a mistake. 句中as引导原因状语从句，“因为.....”, that在这个原因状语从句中又引导it的同位语从句，整句意思是：因为地球是圆的，这是众所周知，(所以)你不该犯这么个错误。

4. 懂了没？不懂再问。我刚好目前在给学生复习状语从句。