主语从句
一、概述：用作主语的从句叫做主语从句。
二.主语从句连接词：
（1）从属连词: that引导的主语从句:引导词that无含义,在句中不做成分,日本英语但不可以省略。
Eg: ：That they will win the match ems unlikely.(他们想赢这场比赛看起来是不可能的）
Eg: ：That she survived the accident is a miracle./a wonder(她在事故中幸免于难简直是奇迹。)
翻译：她的离开使他很伤心。
That she left him cut him to the heart.
（2） 用连词 whether 引导的主语从句:whether有含义(是否),在句中不做成分,不可以省。（注：引导主语从句不能用if）
Eg：Whether she is coming or not doesn’t matter .（她来不来都无关紧要。）
Eg：Whether it is true remains a question. （它是真是假还是个问题。）
翻译：我们明天是否在户外开晚会要看天气而定。
Whether we will hold a party in the open air tomorrow depends on the weather.
（3） 连接代词: 连接代词who, who, whom, which, what, whoever, whomever, whichever, whatever引导的名词性从句中，这些连接词既有疑问意义，又起连接作用，同时在从句中担当一定成分).
Eg：What you need is more practice.（你所需要的是更多的训练。）
Eg：Whatever we do is to rve the people.（我们无论做什么都是为人民服务。）
Eg ：Who will do the job has not been decided.(还没决定谁去做这份工作）
翻译：我想知道的就是怎样使用这台计算机。
What I want to know is how to u the computer.
（4）连接副词：when, where, why, how引导的名词性从句(其连接副词有疑问意义,在句中作时间，地点，原因，方式状语等成分。)
Eg ：Where I spend my summer holiday is none business of yours.（我在哪度假与你无关）
Eg ：When they will come is not known yet.（他们什么时候来还不知道。）
Eg ：How this happened is not clear to anyone. （这事怎样发生的，谁也不清楚）
Eg ：why he did it remains a mystery. （他为什么做那件事依然是一个谜。）
重点1：有时为了考虑句子平衡，it 做形式主语,而将主语从句放在句末（尤其是当谓语较短时）。这分三种情况：
(1) 对于以连词that引导的主语从句，通常用形式主语it代主语从句，此时that可以省略。
Eg ：That the earth moves around the sun is known to all.（地球围绕太阳转，这是众所周知的事。）
=It is known to all （that ）the earth moves around the sun（众所周知地球围绕太阳转。
(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：
Eg ：Whether they would support us was a problem. （他们是否会支持我们还是一个问题。头像文艺）
=It was a problem whether they would support us. 西红柿的功效（他们是否会支持我们还是一个问题。）
(3) 对关系代词型what引导的主语从句，通常直接将主语从句放在句首。如：
What we need is money. 我们需要的是钱。
What I want to know is this. 我想知道的就是这一点。
重点2：固定用法和译法（1） It is +名词+从句
It is a fact that… 事实是……
It is good news that … ……是好消息
It is a question that … ……是个问题
It is common knowledge that … ……是常识
类似的名词还有：a pity；a wonder；a good thing； no wonder； surpri, idea, honor 等。
Eg ：It is a mystery to me how it all happened.:（这一切是怎么发生的是个谜。）
Eg ：It is a pity that you have to leave so soon(真遗憾你这么快就得离开）
Eg ：It is no surpri that he have made such great progress.(他取得的进步这么大，这不足为奇。)
翻译： 很遗憾他没来。
It’s a pity that he didn’t come.
（2） It is +形容词+从句
It is necessary that … 有必要……
It is clear that … 很清楚……
It is likely that … 很可能……
It is important that … 重要的是……
类似的形容词还有：strange; natural; obvious; true; good; wonderful; possible; unlikely; unusual; certain; evident; worth-while; surprising; interesting; astonishing, etc.
Eg ：It is obvious that she will do well in her exam.（很明显她考试成绩会很好。）
Eg ：It was really astonishing that he refud to talk to you .（他拒绝和你说话真是令人惊讶。）
Eg ：It is uncertain whether he is coming or not（他是不是来还没确定）
Eg ：It ems obvious that we can not go on like this.（很明显我们不能这样下去了。）
（3） It is +过去分词+从句
It is said that … 据说……
It is reported that … 据报道……
名人故事400字It has been proved that … 已证明……
It must be proved that… 必须指出……
类似的过去分词还有：known; expected; believed; estimated ;thought; hoped; noted; discusd; required; decided; suggested,etc.
Eg ：It is thought that he is the best player.(巴西龟可以吃吗大家都认为他是最好的选手。藏宝阁手续费)
Eg ：It is estimated that the va is 2000 years old.(据估计这个花瓶有2000年的历史。)
Eg ：It is said that he was killed in the earthquake.(据说他在地震中丧生了）
（3） It is +特殊动词+从句（常用于此句型的动词有appear， happen， em，occur, do
es’t matter ,makes no difference.(无关紧要）
Eg ：It makes no difference whether he will attend the meeting or not.(他是否参加会议都无关紧要）
Eg ：It happened that I was at the school gate at that time.(碰巧，我当时在学校门口。)
Eg ：It does not matter if I misd my train, becau there is another later.
没有赶上这趟火车没有关系，稍晚还有一趟。
翻译：碰巧我昨天看见他了。
Eg ：It happened that I saw him yesterday.。自嘲陆游
三、连词that的省略问题
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 Beijing was a pity. 很遗憾你没去北京飘怎么组词。(that不可省)
It was a pity (that) you didn’t go to Beijing. 很遗憾你没去北京。(that可省)
Ⅰ．选择题：
1. __D___ as much as one-fifth of all timber harvested is not ud.
A. The estimate B. The estimate
C. They are estimated D. It is estimated that
2. ____D_ some mammals came to live in the a is not known.
A. Which B. Since C. Although D. How
