主语从句讲解与练习
主语从句强调句讲解练习
主语从句1．定义：用作主语的从句叫做主语从句。
2．引导主语从句的关联词有三类：(1)从属连词that、whether。
如：如：That they were in truth sisters was clear from the facial resemblance between them.很明显，她们确是亲姐妹，她们的脸型很相似。
Whether he’ll come here isn’t clear. 他是否会来这里还不清楚。
从属连词：that，whether等.that 引导主语从句只起引导作用，本身无实际意义，在主语从句中不充当任何成分，但不能省略。
由whether及其他连词引导的主语从句放在句首，句后都可。
If只能放在句中。
(2) （特殊疑问词）连接代词who, whom, whose, what, which, whoever, whatever, whichever如：___which_______watch was lost is unknown._____what_____she did is not yet known. 她干了什么尚不清楚。
__which________side will win is not clear.Whoever comes is welcome. 不论谁来都欢迎。
(3) （特殊疑问词）连接副词where, when, how, why，wherever，whenever，however。
___________ he did it remains a mystery.When they will start is not known yet.How this happened is not clear to anyone. 这事怎样发生的，谁也不清楚Wherever you are is my home ---- my only home.你所在的任何地方就是我的家----我唯一的家。
主语从句讲解及习题
名词性从句之主语从句一、名词性从句概述：在句子中起名词作用的各种从句统称为名词性从句。
根据它们在句中的语法作用，这类从句又可分为主语从句、同位语从句、表语从句和宾语从句。
二、主语从句定义：在句中起主语作用的从句称为主语从句。
引导主语从句的连接词主要有：单纯连词(that, whether/ if)、连接代词(what, whatever, who, whoever, whom, whose, which, whichever 等)和连接副词(when, where, why, how, whenever, wherever, however 等)。
1)that引导的主语从句(1)由连词that引导的主语从句:引导词that无含义/在句中不做成分/不可以省。
例如：That you will win the medal seems unlikely.你能得奖看起来不大可能。
That light travels in straight lines is known to all.众所周知，光沿直线传播。
That you don’t like him is none of my business.你不喜欢他不管我的事。
(2)形式主语it替代主语从句位于句首，that引导真正的主语从句会放到句子的后面。
常用的句式主要有如下几种：1.It+系动词+形容词+that从句。
如：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; quite; unusual; certain; evident; worth-while; surprising; interesting; astonishing, etc.例如：It was really astonishing that he refused to talk to you.It is essential that he should be here by the weekend.It seems obvious that we can not go on like this.It is necessary that you (should)master the computer.It is important that a student learn English well.It' s clear that they badly need help.It is likely that a hurricane will arrive soon.知识拓展：在“It is necessary / important/surprising/strange/unthinkable/unbelievable/incredible+that 从句”这类主语从句结构中，从句中谓语动词常用(should) +动词原形”，形式，即要用虚拟语气should 可省略。
理解中的主语从句和表语从句练习题及
理解中的主语从句和表语从句练习题及解答主语从句和表语从句是英语语法中重要的从句结构，它们在句子中起到了关键的作用。
本文将为您提供一些关于主语从句和表语从句的练习题及解析，帮助您进一步理解和掌握这两种从句。
练习题一：主语从句1. _________ is important to stay hydrated during hot summer days.A. HowB. WhenC. ThatD. It2. _________ she told me was a complete surprise.A. WhatB. WhoC. WhenD. Where3. _________ will attend the meeting is not yet confirmed.A. ThatB. WhatC. HowD. Who4. _________ the book is not easy to understand.A. WhetherB. ThatC. WhatD. When5. _________ we need is more time to complete the project.A. WhyB. WhatC. WhenD. How练习题二：表语从句1. My biggest fear is _________.A. that I will fail the examB. when the exam will startC. how difficult the exam isD. why I need to take the exam2. The truth is _________ most people are not aware of the consequences.A. whenB. whereC. whatD. why3. Our goal is _________ a sustainable future for generations to come.A. whyB. howC. whatD. when4. The problem is _________ we don't have enough resources.A. howB. whyC. whenD. where5. His belief is _________ hard work and dedication are key to success.A. whatB. thatC. whenD. where解析：练习题一：主语从句1. D. It。
主语从句讲解及练习
主语从句讲解及练习什么是主语从句？主语从句是由一个从句充当主语的句子结构，它由连接词引导，用来说明主语的内容或者起到引入主题的作用。
主语从句的引导词一般情况下，主语从句由以下连接词引导：- that- whether/if- who/whom- which- what- whatever- whoever- whichever主语从句的用法主语从句在句子中承担主语的角色，可以帮助我们表达某个动作、状态、事件或者事实的主题。
下面是一些常见的用法示例：1. 表达事实或真理：例如：That he is innocent is beyond doubt.（他的无辜是毫无疑问的。
）2. 表达感觉或观点：例如：What he said is very interesting.（他说的话很有趣。
）3. 引导宾语从句：例如：I believe that he will succeed.（我相信他会成功。
）主语从句的位置一般情况下，主语从句位于句首或者句中，具体位置取决于句子的结构和语境。
主语从句的练题请根据下面的句子，填写合适的主语从句：1. __________ you did yesterday surprised everyone.（你昨天做的事让大家都吃惊。
）2. __________ will happen remains unknown.（将会发生什么还不确定。
）3. __________ is important to study hard.（努力研究是很重要的。
）5. __________ we need is more time.（我们所需要的是更多的时间。
）参考答案：1. What2. What3. It4. Whether/if5. What以上是对主语从句的讲解及练习，希望对你的学习有所帮助。
主语从句超全讲解加练习
1〕从属连词：that，whether等.that 引导主语从句只起引导作用，本身无实际意义，在主语从句中不充当任何成分，但不能省略。
That he will win is certain.他肯定会赢。
Whether he’ll come here isn’t clear. 他是否会来这里还不清楚。
注意: 由that 引导的主语从句有时为了使句子结构平衡, 防止“头重脚轻”, 常用it 作形式主语, 而把从句放在后面。
例如:1. That he will refuse this piece of advice is impossible.2.That they should like each other is natural.这样就构成了下面一些常用句型:1) It is + n. +从句It is a pity/shame that... 遗憾的是……It is a surprise that…令人惊奇的是…It is a fact that… …是事实It is common knowledge that… …是常识______________(很遗憾)we lost the match._____________(这是事实)he cheated in the exam.2) It is + adj. +从句It’s certain that… 肯定…It is possible that... 很可能……It is unlikely that... 不可能……It is obvious that… 很明显…It is necessary \important \natural\... that…+(should) do________________(很可能)she will come back tomorrow.*_________________(很明显)this measure is effective.3) It +不及物动词+从句It happened that... 碰巧……It occurred to me that…我突然想起…_______________(刚好)I came into the office at that time.*____________________(我突然想起)I forget to sent the letter.4) 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..人们相信/认为……It is suggested that + (should〕do... 建议……__________________(据报道)20 people were killed in the accident.*_______________(建议)we should eat more vegetable and do more exercise.2.连接代词who ，what ，which, whatever, whichever, whoever(Who, whom, which, what可以和ever构成合成词，和what一样引导从句，ever起到强调作用。
高中英语主语从句练习题20题含答案解析
高中英语主语从句练习题20题含答案解析1._____ he will come or not is still a question.A.ThatB.WhetherC.WhoD.What答案解析：B。
“Whether...or not”是固定搭配，表示“是否”。
A 选项that 在主语从句中不表示“是否”的意思；C 选项who 表示“谁”，不符合语境；D 选项what 表示“什么”，也不符合题意。
2._____ surprised us most was his attitude.A.ThatB.WhetherC.WhoD.What答案解析：D。
what 在主语从句中充当主语，表示“什么”。
A 选项that 在主语从句中无实际意义，只起连接作用；B 选项whether 表示“是否”；C 选项who 表示“谁”，在这里都不符合语境。
3._____ is known to us all is that the earth is round.A.ThatB.WhetherC.WhoD.What答案解析：A。
“That is known to us all”是固定句式，that 在主语从句中无实际意义，只起连接作用。
B 选项whether 表示“是否”；C 选项who 表示“谁”；D 选项what 表示“什么”，在这里都不合适。
4._____ he has done is very important.A.ThatB.WhetherC.WhoD.What答案解析：D。
what 在主语从句中充当宾语，表示“他所做的事情”。
A 选项that 在主语从句中无实际意义，只起连接作用；B 选项whether 表示“是否”；C 选项who 表示“谁”，在这里都不符合语境。
5._____ will win the game is not clear.A.ThatB.WhetherC.WhoD.What答案解析：C。
根据语境，“谁会赢得比赛还不清楚”，who 在主语从句中充当主语，表示“谁”。
语法讲解：主语从句练习
主语从句练习
翻译（要求运用主语从句）
1.学校为学生提供大量的技巧性课程是很有必要的。
2.谁将会成为我们的班长还不确定。
3.我们应该向谁学习值得思考。
4.政府应该要做的是提倡人们节约水资源。
5.无论你做什么都不会影响你在我心目中的地位。
6.导致灾难的原因至今还很神秘。
7.他会那样做真是太让人吃惊了。
8.他终于实现了想去巴黎的愿望。
9.我们可以采取的第一项措施来是植树来吸收二氧化碳，从而抑制全球变暖。
10.非常奇怪，人们对于动植物濒临灭绝完全无动于衷。
主语从句表语从句学案和专项练习
Subject Clause and Predicative ClauseⅠ. 主语从句(Subject Clause)一定义：__________________________________________________.1. He is right .2. What he said is right .二.主语从句引导词1.主语从句的引导词与宾语从句一样。
〔但不用if 〔是否〕，只能用whether(是否)〕1) that 2) whether3) what , which ,who, whom, whose, whatever , whichever.....4) where , when , why, how, wherever, whenever .....5) how many , what color, how far等。
2. 引导主语从句的关联词除起连接句子的作用，绝大多数关联词在主从中要充当一定的句子成分。
3. 主语从句的语序是：关联词+S+V三. 主语从句引导词的用法:1. that 的用法：that 引导句意完整, 意义明确不缺成分的述句；无词义，在主从中不充当句子成分，不能省略。
仿照例子改写句子改成相应的主语从句Model: There is life on another planet (在另外的星球上)〔that 引导的主从〕 It is almost impossible.→That there is life on another planetis almost impossible(主从) s v.1). The scientist will give us a lecture ne*t week. It is true. →2). You don’t like him. It is none of my business.(不关我的事) →3).Her hair was turning gray(灰色). It worried her bit.→4). He told her everything. It is probable.→5). He sings so well. It is no surprise.→2. whether 的用法: whether引导的主从不缺句子成分，句意不完整，表达一种不确定，不明确的概念；whether当"是否"讲，在主从中不充当句子成分。
主语从句讲解加练习(1)
4.(__W__h_o_ can join in the sport meet) is decided by the teacher. 5.(W__h_e_t_h_e_r_ it will rain or not) is not clear.
It is a pity/shame that... 遗憾的是…… It is a surprise that…令人惊奇的是… It is a fact that… …是事实 It is common knowledge that… …是常识
*__It_i_s_a__p_i_ty__th_a_t__(很遗憾)we lost the match.
Unit4 Grammar
Noun clauses as the subject
名词性从句
主语
Find the subjects in the following sentences.
1. A tree has fallen across the road. 2. You are a student. 3. To find your way can be a problem. 4. Smoking is harmful to you. 5. What she said is not yet known. 6. That we shall be late is certain. 7. It’s certain that we shall be late.
最新主语从句详细讲解及综合练习资料
主语从句一、概念：在复合句中起主语作用的从句叫主语从句。
（一）连接词从属连词：that、whether；关系代词：who, what, which , whom, whose, whatever, whoever, whomever, whichever；关系副词：when, where, how, why, however, whenever, wherever等；例：What he said is true.That you don’t like him is none of my business.Whether the football game will be played depends on the weather.主语从句的时态：不受主句的时态影响和限制。
（1）______ he finished writing the composition in such a short time ______(惊讶) us all.（2）______we will go for an outing tomorrow ______（remains，remained）unknown.（3）______ will be our monitor ______(be) decided yet.（4）______we must study for ______ (be) a question of great importance.（5）______ caused the accident ______（remains，remained）unknown.（6）______ you did ______ (be)right.（7）______ watch ______(be) lost is unknown.（8）______we need ______(be) time.（9）______ we need ______(be) good doctors.小结:（1)主语从句的时态：不受主句的时态影响和限制。
高考语法 名词性从句之主语从句与表语从句 讲解及练习(附答案)
名词性从句1 主语从句：在复合句中充当主语成分的句⼦子叫主语从句 1.1 主语从句的引导词 1.2 主语从句的形式Conlusion 1:主语从句作主语时，谓语动词一般用单数（第三人称）形式。
Conlusion 2:连词That在句中无实际意义，不能省略。
Conlusion 3:whether引导的主语从句可放在句首，但if不能。
Conlusion 4:主语从句中连词that/whether等不能重复使用。
Conlusion 5:what引导的主语从句，可根据表语决定主句的单复数形式。
Conlusion 6:为了平衡句子结构，主语从句大多可改写为it形式主语形式。
从属连词连接副词连接代词引导词that,whether,if when, why, where, how, whenever, wherever, however what, who, whom, which, whatever,whoever, whomever, whichever形式说明⽰示例that 引导的主语从句置于句⾸首、that 在主语从句中不做任何成分、不可省略他要来看望我们，这使我们很⾼高兴。
形式评语it代替主语从句It + is/was + adj. +从句对于学⽣生来说很明显的是，他们要为未来做好准备。
“It is/was + necessary/important/surprising/strange/unbelievable/obvious…+从句”结构中，从句谓语动词用“should+动词原形”，should可以省略It + is/was + 名词 +从句我们的希望是，我们都能通过考试。
It + is/was + V-ed +从句据宣布，该计划已经顺利通过。
“It is/was + suggested/advised/ordered/insisted/required/demanded…+从句”结构中，从句谓语动词用“should+动词原形”，should可以省略It + is/was + 特殊动词 +从句(happen,occur,seem,appear…)你似乎不同意这个计划。
主语从句 讲解与练习
C.It+be+过去分词 (said, reported, thought, expected, announced, arranged, etc.) +that从句 It is said that Mr. Green has arrived in Beijing.
D.It+(seems, happens, appears等不及物动词及短 语)+that从句 It happened that I was out that day. It seems that she is not in a good mood.
E.It+(doesn’t matter, makes no difference,etc)+ 连接代词或连接副词引导的 主语从句 It doesn’t matter whether she will come or not.
ቤተ መጻሕፍቲ ባይዱ
主语从句与强调句的区别
1). 在主语从句中，把It be … that 去掉之后，句子成分不完整；在 强调句中，则是个完整的句子； 2). 主语从句多种引导词；强调句 的引导词只有：that, who。
What you said is of great importance. How he was successful is still a puzzle.
3.主语从句置于句首时，必 须由连接词引导，不能省略 这些连接词；但是如果用it 作形式主语，主语从句后置 时，则从属连词that可以省 略。 That he is a hero is known by everyone.
Subject Clauses 主语从句
A tree has fallen across the road.
高中主语从句练习题及讲解答案
高中主语从句练习题及讲解答案# 高中主语从句练习题及讲解答案## 练习题1. 题目一：尽管他很年轻，但他已经是一位成功的企业家了。
- 例句：_________ he is very young, he has already becomea successful entrepreneur.2. 题目二：无论你什么时候来，我都会在这里等你。
- 例句：_________ you come, I will be here waiting for you.3. 题目三：他相信他能通过这次考试，这让他的父母感到非常高兴。
- 例句：He believes that he can pass the exam, which makes his parents very happy.4. 题目四：我们不知道他是否已经完成了作业。
- 例句：We don't know _________ he has finished his homework or not.5. 题目五：她害怕黑暗，这是众所周知的。
- 例句：She is afraid of the dark, which is _________.## 讲解主语从句是作为动词或介词的宾语的从句，它通常位于句首。
主语从句可以由连接词that, if, whether等引导。
- that引导的主语从句：用来陈述一个事实，通常可以省略。
- if/whether引导的主语从句：用来表达“是否”，通常不能省略。
## 答案1. 答案一： Although/Though _________ he is very young, hehas already become a successful entrepreneur.- 讲解：这里使用了“Although”或“Though”来引导让步状语从句，表示尽管他年轻，但他已经成功。
2. 答案二： Whenever _________ you come, I will be herewaiting for you.- 讲解：“Whenever”引导主语从句，表示无论何时你来。
英语主语从句语法详解
如何正确使用英语主语从句一、主语从句的概念和特点主语从句是指在句子中充当主语的从句，即表示句子的主体或说话者的观点、想法、感受等的从句。
主语从句可以直接位于主语的位置，也可以由形式主语it代替，而将从句放在句子末尾。
主语从句要用陈述语序，即主语在前，谓语在后，不用倒装或省略。
主语从句后的谓语动词用第三人称单数，与从句的主语无关。
例如：What he said is true. 他说的是真的。
（主语从句直接位于主语的位置）It is true that he said so. 他说的是真的。
（主语从句由形式主语it代替，放在句子末尾）Whether he will come is not certain. 他是否会来还不确定。
（主语从句要用陈述语序，不用倒装）The fact that he is late worries me. 他迟到的事实让我担心。
（主语从句后的谓语动词用第三人称单数，与从句的主语无关）二、主语从句的引导词和用法主语从句通常由以下几类词引导：从属连词：that, whether等。
that通常只起连接作用，无实际意义，有时可以省略。
whether表示是否，后面可以跟or not。
例如：That he is honest is known to all. 他诚实是众所周知的。
（that可以省略）Whether he will come or not is not certain. 他是否会来还不确定。
（whether表示是否，后面跟or not）连接代词：who, whom, whose, which, what等。
连接代词在从句中充当主语、宾语、定语等成分，有实际意义，不能省略。
例如：Who will go with you is not decided yet. 谁将和你一起去还没有决定。
（who在从句中充当主语）What he needs is more practice. 他需要的是更多的练习。
高中英语主语从句用法练习题40题含答案解析
高中英语主语从句用法练习题40题含答案解析1._____ he will come to the party is still uncertain.A.ThatB.WhetherC.WhatD.Who答案解析：B。
“Whether he will come to the party”是主语从句，在这个句子中“whether”表示“是否”，整个主语从句的意思是“他是否会来参加聚会”。
“that”引导主语从句时在从句中不充当任何成分，只起连接作用，且没有实际意义，此句中意思不符。
“what”在主语从句中要充当成分，此句不缺成分。
“who”在主语从句中表示“谁”，此句不是问谁会来参加聚会。
2._____ she won the first prize surprised all of us.A.ThatB.WhetherC.WhatD.When答案解析：A。
“That she won the first prize”是主语从句，“that”在从句中不充当任何成分，只起连接作用，此句中“她赢得一等奖这件事让我们所有人都很惊讶”，用“that”符合语法规则。
“whether”表示“是否”，不符合句意。
“what”在主语从句中要充当成分，此句不缺成分。
“when”表示“什么时候”，不符合句意。
3._____ is important is that we should study hard.A.ThatB.WhetherC.WhatD.Who答案解析：C。
“What is important”是主语从句，“what”在从句中充当主语，表示“重要的事情”。
“that”在主语从句中不充当成分，此句缺主语。
“whether”表示“是否”，不符合句意。
“who”表示“谁”，不符合句意。
4._____ he said at the meeting was very important.A.ThatB.WhetherC.WhatD.Who答案解析：C。
主语从句讲解和练习题
主语从句讲解和练习题公司内部编号：（GOOD-TMMT-MMUT-UUPTY-UUYY-DTTI-高考英语主语从句定义：用作主语的从句叫主语从句，它是名词性从句之一。
主语从句的时态：不受主句的时态影响和限制。
引导主语从句的连接词有：从属连词: that, whether；连接代词: who (whoever), whom, whose, what (whatever)和which (whichever)；连接副词: when, where, how和why。
连接词：1. 从属连词：that， whether1）that引导主语从句只起引导作用，在主语从句中不充当任何成分，that本身无实际意义，但不能省略。
2）whether意为“是否”，放在句首句末皆可。
由whether引导的名词从句做主语，表语，介词宾语，同位语时！不可用if代替。
price will go up is certain.b. Whether they would support us was a problem. 他们是否会支持我们还是一个问题。
2. 连接代词who ，what ，which, whatever, whichever, whoever (Who, whom, which, what可以和ever构成合成词，和what一样引导从句，ever起到强调作用。
此类主语从句不能用形式主语it引导，它们在句子中担任成分，不能省略，语序为陈述语序，既有疑问含义,又起连接作用,同时在从句中充当各种成分。
Which side will win is not clear. Whoever breaks the law will be punished.Whatever he did is right. Who killed the scientist remains a question. 1）What和that引导的主语从句的区别：that 只起引导作用，不充当任何成分，没有意思。
主语从句超全练习试题和答案解析
主语从句练习题[即学即用]I. 用适当的词填空，使句子意思完整。
1. ______ he didn’t attend the meeting yesterday wasn’t quite clear.2. The Foreign Minister said, “It is our hope ______ the two sides will work towards peace.”3. ______ team will win the match is still unknown.4. ______ comes to the party will receive a present.5. ______ Mary has left is still a question.6. It’s reported ______ three people were killed in the accident and five were hurt badly.7. ______ he solved the problem successfully interested all of us.8. We usually think ______ we can’t get seems better than what we have.9. It is a fact ______ English is being accepted as an international language.10. ______ is to be sent there to solve the problem hasn’t been decided. II. 下列各句中均有一处错误，请改正。
1. That the old man’s son wanted to know was where the gold had been hidden.2. It is reported when China has successfully sent Shenzhou VI spaceship into space.3. If he can finish his task on time is of great importance.4. Whether the 2008 Olympic Games will be held in Beijing excited the whole nation.5. After Yang Liwei succeeded in circling the earth, which our astronauts desire to do is walk in space.6. Whatever leaves the room last ought to turn off the lights.7. Why they will solve the serious problem today has not been decided.8. When will win the English competition is still a problem.9. How our spring sports meet will be held or not this week is not known yet.10. It’s strange when he should have gone away without telling us. GRAMMAR主语从句学习指导[寻规找矩] 请观察下列句子，注意主语从句的用法。
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主语从句一、概述：在句子中起名词作用的各种从句统称为名词性从句。
根据它们在句中的语法作用，这类从句又可分为主语从句、同位语从句、表语从句和宾语从句。
二.主语从句主要有三类：（1）由连词that引导的主语从句:引导词that无含义,在句中不做成分,不可以省。
例如：That you will win the medal seems unlikely.你想获得奖牌看起来是不可能的。
That you are so indifferent bothers me.你如此冷淡使我很烦恼。
That she survived the accident is a miracle.她在事故中幸免于难简直是奇迹。
（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。
例如：Whether she is coming or not doesn’t matter too much.她来不来都无关紧要。
（3）用连接代词引导的主语从句(在由连接代词who, whose, whom, which, what, whoever, whomever, whichever, whatever引导的名词性从句中，其连接代词在句中起名词性作用，担当一定成分).例如：What you need is more practice.你所需要的是更多的训练。
What I want to know is this. 我想知道的就是这事。
Whatever we do is to serve the people.我们无论做什么都是为人民服务。
（4）用连接副词when, where, why, how引导的名词性从句(其连接副词有含义,在句中作状语。
)eg:Where we should leave it is a problem.When they will come hasn’t been made pubic.他们什么时候来还不知道。
三.注意点:1.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）。
例如：That light travels in straight lines is known to all.光沿直线传播，这是众所周知的事。
=It is known to all that light travels in straight lines.众所周知光沿直线传播。
When the plane is to take off has not been announced .飞机何时起飞还没有宣布。
= It has not been announced when the plane is to take off.还没有宣布飞机何时起飞。
(当what引导的主语从句表示“…的东西”时，一般不用it作形式主语。
)错:It is a book what he wants.对:What he wants is a book. 他想要的是本书。
例如：Has it been settled who will be sent to carry out the task ?谁将被派去执行这项任务决定了吗？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； surprise 等。
例如：It is a mystery to me how it all happened.这一切是怎么发生的是个谜。
It is common knowledge that the whale is not a fish.鲸鱼不是鱼，这是常识。
It is no surprise that Bob should have won the game.鲍勃会赢得这场比赛，这不足为奇。
（2） It is +形容词+从句It is n ecessary 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; quite; unusual; certain; evident; worth-while; surprising; interesting; astonishing, etc.例如：It is obvious that conductors and insulators are both important in industry.很明显导体和绝缘体在工业中都很重要。
It is doubtful whether she will be able to come.她是否能来令人怀疑。
It was really astonishing that he refused to talk to you .他拒绝和你说话真是令人惊讶。
It is essential that he should be here by the weekend .周末之前，他应该到这里是必要的。
It seems 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……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; estimated; expected; believed; thought; hoped; noted; discussed; required; decided; suggested; demanded; made clear; found out,etc.例如：It is thought that he is the best player.大家都认为他是最好的选手。
It is estimated that the vase is 2000 years old.据估计这个花瓶有2000年的历史。
It is used to be thought that a new star must be due to a collision between two stars. 过去一直认为新星是由于两颗星星之间碰撞产生的。
It has not been made clear when the new road is to be opened to traffic. 还没弄清楚这条路将开始通车。
It does not matter if I missed my train, because there is another later. 没有赶上这趟火车没有关系，稍晚还有一趟。
It happened that I saw him yesterday.碰巧我昨天看见他了。
当“及物动词 + 宾语”较短时，也可用这种结构。
例如：It shocked me that Peter did not tell anybody where he was.让我吃惊的是彼得没有告诉任何人他在哪里。
It does not interest me whether you go or not.我对你去不去不感兴趣。
2.只用whether不用if引导主语从句.Ⅰ．选择题：1. _____ as much as one-fifth of all timber harvested is not used.A. The estimateB. The estimateC. They are estimatedD. It is estimated that2. _____ some mammals came to live in the sea is not known.A. WhichB. SinceC. AlthoughD. How3. _____ we have achieved is attributed to the guidance of our parents.A. WhoeverB. WhateverC. HoweverD. That4. _____ wealthy does not necessarily mean that a man is greedy.A. For the reason that he isB. Just because he isC. The reason of beingD. That he is5. Although _____ happened in this developed country sounds like science fiction, it could occur elsewhere in the world.A. whichB. whatC. howD. it6. _____ she had forgotten to take her notebook.A. That occurred to herB. She occurred thatC. To her that occurredD. It occurred to her that7. I am sure that _____ she said is wrong.A. whichB. allC. thisD. what8. We lost our way in the forest, and _____ made matters worse was that it was getting dark.A. thatB. whichC. itD. what9. _____ some mammals came to live in the sea is not known.A. WhichB. SinceC. AlthoughD. How10. _____ or not is still uncertain.A. He’s comingB. If he is comingC. That comingD. Whether he’s coming11. It’s_____ he’ll be able to come.A. doubt whetherB. doubtfulC. doubt itD. doubtful whether12. _____ he is at work in the heart of the big city or at home in the quiet suburb, Dick’s life is tied to machines.A. WhetherB. TillC. IfD. Unless13. _____ he saw both surprised and frightened him.A. ThatB. WhenC. WhatD. Which14. _____ is a spell of warm sunshine.A. What do we all need.B. What all we needC. What we needD. What we all need15. _____ is a pity that he should feel so upset.A. WhatB. ThatC. HeD. It16. _____ a spoonful of soil can tell us so much about the structure and early history of the moon.A. RemarkableB. Quite remarkablyC. It is remarkable thatD. It is remarkable fact that17. _____ you nominate will be elected.A. WhoB. WhomC. WhomeverD. That’s18. _____ book you borrow must be returned within a week.A. WhatB. WhichC. WhicheverD. That’s19. _____ of us gets home first starts cooking.A. WhoB. WhichC. WhicheverD. Anyone20. _____orders he gives are obeyed.A. WhicheverB. WhichC. WhateverD. What。