it is a pity that是什么从句

主语从句。It is a pity that…是it用法的一个句型，it是形式主语，that引导的从句是主语从句，意为"很遗憾…"

it is a pity that是什么从句

句型是It be+名词+that从句，这是一个由形式主语it代替的主语从句。

主语从句是名词性从句的一种，名词性从句指在句子中的作用相当于名词的从句，所以主语从句就是在主语的位置上是一个句子。是这个样子的：That you didn't go to the talk was a pity.你没去听报告真遗憾。

主语从句在复合句中作主句的主语，引导主语从句的词有从属连词that, whether以及连接代词who, what,which, whoever, whatever, whichever和连接副词when, where, why, how等。

主语从句介绍

主语从句：充当主语的从句。用于主语过长，要用句子表达的情况。

That he will come is certain.  他确定会来。

从句作主语。

主语从句通常由连词that和whether、连接代词或连接副词引导。

1. that引导（没有意思）

That he is still alive is a wonder. 他还活着，真是奇迹。

That we shall be late is certain. 我们要晚了，这是确定无疑的。

2. whether引导（是否）

Whether it will do us harm remains to be seen. 是否对我们有害还要看一看。

Whether they would support us was a problem. 他们是否会支持我们还是一个问题。

3. 连接代词引导

What we need is money. 我们需要的是钱。

Whichever you want is yours. 你要哪个哪个就是你的。

4. 连接副词引导

When we arrive doesn’t matter. 什么时候到没有关系。

How it was done was a mystery. 这是怎样做的是一个谜。

有时为了考虑句子平衡，通常在主语从句处使用形式主语it，而将真正的主语从句移至句末。

（1） 对于以连词that引导的主语从句，通常用形式主语代主语从句：

It’s a pity that he didn’t come. 很遗憾他没来。

It is important that he should know about this. 他必须知道此事。

（2） 对于以连接代词（副词）引导的主语从句，可以使用形式主语代主语从句，也可直接在句首使用主语从句：

Whether they would support us was a problem. 他们是否会支持我们还是一个问题。

It was a problem whether they would support us. 他们是否会支持我们还是一个问题。

引导主语从句的连词that 有时可省，有时不能省，其原则是：若that引导的主语从句直接位于句首，则that不能省略；若that引导的主语从句位于句末，而在句首使用了形式主语it，则that可以省略：

That you didn’t go to the talk was a pity. 很遗憾你没去听报告。（that不可省）

It was a pity （that） you didn’t go to the talk. 很遗憾你没去听报告。（that可省）

主语从句常用句型

1）It is + adj. / n. +从句

It is a pity/shame that…遗憾的是……

It is possible that…很可能……

It is unlikely that…不可能……

2）It +不及物动词+从句

It seems/appears that…似乎……

It happened that…碰巧……

3）It + be +过去分词+从句

It is said that…据说……

It is known to all that…众所周知……

It is reported that…据报道……

It is believed that…据信……；人们相信……

It is suggested that…有人建议……

It must be pointed out that…必须指出……

It has been proved that…已证明……

例如：

It is believed that at least a score ofbuildings were damaged or destroyed.

据信，至少有二十座楼房遭到破坏或彻底毁掉。

It is suggested that the meeting should beput off.

有人建议会议延期召开。

It's reported that three people were killedin the accident and five were hurt badly.

据报道，事故中三人丧生，五人重伤。

It is known to all that Taiwan is aninseparable part of China.

众所周知，台湾是中国不可分割的一部分。