主语从句和表语从句的具体解释

主语从句和表语从句的具体解释
主语从句和表语从句的具体解释

主语从句和表语从句的具体解释
定义
　　在复合句中充当主语成分的句子叫做主语从句.
第一部分
　　常规主语从句,即句子在复合句中充当一个主语 　　主语从句的时态：不受主句的时态影响和限制. 　　（1）That he finished writing the composition in such a short time surprised us all. 　　（2）Whether we will go for an outing tomorrow remains unknown. 　　（3）Who will be our monitor hasn't been decided yet. 　　（4） Whom we must study for is a question of great importance. 　　（5）What caused the accident remains unknown. 　　（6）Whatever you did is right. 　　（7）Who the watch belongs to was lost is unknown. 　　（8）What we need is time. 　　（9）What we need are good doctors. 　　小结: 　　（1)引导主语从句连词有that,whether,who,what,whatever等 　　（2)连词位于句首不能省略 　　（3)主语从句大多数情况下视为第三人称单数,但也有例外,如例（9）
第二部分
　　为了防止句子头重脚轻,通常把形式主语it放在主语位置,真正主语搁置于句末 　　（1）It is certain that he will win the match. 　　（2）It is true that he has made a very important discovery in chemistry. 　　（3）It is very likely that they will hold a meeting. 　　（4）It is strange that he should do that. 　　（5）It is important that we all should attend the meeting. 　　（6）It is strange that the man should have stuck to his silly ideas. 　　（7）It is a pity that we won't be able to go to the south to spend our summer vacation. 　　（8）It is still a mystery what caused the accident. 　　（9）It is said that he has gone to shanghai.(=He is said to have gone to shanghai) 　　（10）It is known to all that the gun powder was first invented by the Chinese. 　　（11）It is suggested that the work should be done with great care. 　　（12）It seems that he has seen the film.(=He seems to have seen the film) 　　（13）It happened that the two cheats were there. (=The two cheats happened to be there) 　　小结: 　　（1)以that 引出的主语从句,常以形式主语it引导. It is +形容词/名词/某些动词ed + that 从句. 　　（2) 在有些that从句中要用虚拟语气 (should+do/should+have done)例句4,5,6,11.编辑本段主语从句的用法
　　主语从句与宾语从句两者的用法和在句中的作用是不同的,下面从它们的各自用法来介绍. 　　一．主语从句 　　主语从句 定义:在句子中担当主语的是一个从句,这个从句就叫做主语从句. 　　主语从句是在复合句中充当主语的从句,通常放在主句谓语动词之前或由形式主语it代替,而本身放在句子末尾. 　　1. It 作形式主语和it引导强调句的比较 　　①主语从句常用it作形式主语,一般常用句型为：It is+{名词/形容词/过去分词}+主语从句例如： 　　It is still a question whether she will come or not. 　　It is strange that you should like him. 　　It is still unknown which team will win the match. 　　另外,还有一些比较多见的结构： 　　It turned out that……； 　　It has been proved that……; 　　It happened/occurred that……； 　　It is well-known that……等等 　　②而强调句则不同,它的结构是：It+be+被强调部分+that+从句 　　强调主语：It is the times that produce their heroes.时势造英雄 　　强调宾语：It is English that Prof.Lin teaches us. 　　强调状语：It was in shanghai that I saw the film. 　　判断是否是强调句有一个方法,就是将that以后的“句子的其余部分”拿出来单独看,看有没有缺成分,缺的是什么成分,再把谓语动词后面that前面的那部分,带到你认为缺成分的地方,如果放进去是一句完整的句子了,那就说明是强调句. 　　2. 用it 作形式主语的结构 　　(1) It is +名词+that从句 　　It is a fact that … 事实是… 　　It is an honor that …非常荣幸 　　It is common knowledge that …是常识 　　(2) it is +形容词+that从句 　　It is natural that… 很自然… 　　It is strange that… 奇怪的是… 　　(3) it +不及物动词+that从句 　　It seems that… 似乎… 　　It happened that… 碰巧… 　　(4) it is+过去分词+that从句 　　It is reported that… 据报道… 　　It has been proved that… 已证实… 　　3. 主语从句不可位于句首的五种情况 　　(1) if 引导的主语从句不可居于复合句句首. 　　(2) It is said , (reported) …结构中的主语从句不可提前.例如： 　　It is said that President Jingo will visit our school next week. 　　(3) It happens…, It occurs… 结构中的主语从句不可提前.例如： 　　It occurred to him that he failed in the examination. 　　(4) It doesn’t matter how/whether …结构中的主语从句不可提前.例如： 　　It doesn’t matter whether he is wrong or not. 　　(5) 含主语从句的复合句是疑问句时,主语从句不可提前.例如： 　　Is it likely that it will rain in the evening? 　　4. What 与that 在引导主语从句时的区别 　　What 引导主语从句时在从句中充当句子成分,如主语．宾语．表语,而that 则不然.例如： 　　What you said yesterday is right.
定义
　　
表语从句
表语从句定义：在一个复合句中,从句作的是主语的表语成分.
A
　　The problem is puzzling. 　　这个问题令人困惑 　　主语,连系动词,形容词作表语 　　The problem is when we can get a pay rise. 　　问题是什么时候我们可以得到加薪. 　　主语 连系动词 一个句子作表语---表语从句
B
　　连接表语从句的连接词有：that, what, who, when, where, which, why,whether,how.whoever,whomever,whichever ,whatever等 　　He has become a teacher. 　　他已经成为一名教师. 　　He has become what he wanted to be ten years ago. 　　他已经成为了他10年前想成为的. 　　She has remained there for an hour. 　　她曾在那里停留了一个小时. 　　She has remained where I stood yesterday for an hour. 　　她一直在我昨天站的地方站了一个小时. 　　His suggestion is good. 　　他的建议是好的. 　　His suggestion is that we should stay calm. 　　他的建议是,我们应该保持冷静. 　　The question is confusing. 　　这个问题令人困惑. 　　The question is when he can arrive at the hotel. 　　问题是,他什么时候可以到达酒店. 　　Who will travel with me to Beijing tomorrow.谁与我明天将前往北京. 　　Why he cried yesterday. 　　昨天他为什么哭. 　　How I can persuade her to join us in the party. 　　我怎么能说服她加入我们的派对. 　　Whether the enemy is marching towards us. 　　是否敌人正向我们行进.编辑本段注意
A
　　表语从句一定要用陈述语序. 　　False: The question is when can he arrive at the hotel. 　　Right: The question is when he can arrive at the hotel.
B
　　不可以用if,而用whether 连接表语从句(as if 例外）. 　　引导宾语从句时可以互换if/whether 位于介词后要用whether 　　位于句首时要用whether 　　引导表语从句,主语从句,同位语从句时要用whether 　　False: The question is if the enemy is marching towards us. 　　Right: The question is whether the enemy is marching towards us. 　　Right: It looked as if he had understood this question.
C
　　不像宾语从句,在有表语从句的复合句中,主句时态和从句时态可以不一致. 　　Right: The question is who will travel with me to Beijing tomorrow. 　　Right: The question is why he cried yesterday.
D
　　that在表语从句中不可以省掉.编辑本段基本用法
　　表语从句只能置于主句之后,而主句的动词只能是连系动词. 　　名词性从句在be等系动词后作表语时被称为表语从句 　　例如： The problem is how we can get the things we need.问题是我们怎样能弄到我们需要的东西. (how 在表语从句中充当方式状语) 　　The scissors are not what I need. 这把剪刀不是我所需要的.(what 在表语从句中充当宾语) 　　What I told him was that I would find him a good play. 我告诉他的是我会给他找个好剧本.(what在主语从句中作直接宾语, that作为表语从句的引导词在该表语从句中不充当句子成分, 不能省略) 　　That is what I want to tell you.那就是我想要对你讲的.(what在表语从句中充当直接宾语) 　　That is why she failed to pass the exam. 那就是她考试不及格的原因.(why 在表语从句中充当原因状语)编辑本段注意
　　“That is why...”是常用句型, 意为“这就是……的原因/因此……”, 其中why引导的名词性从句在句中作表语, 该句型通常用于针对前面已经说明过的原因进行总结, 又如： That is why you see this old woman before you know, Jeanne. 珍妮, 这就是现在这个老太婆出现在你面前的原因.(前文提到Jeanne对老妇人显得苍老憔悴深感诧异, 说话人对她讲述了其中的原因之后,用这一句来进行概括).// That is why I came. 这就是我来的原因. 　　下面是两个与“That is why...”形式相似的结构, 它们与“That is why...”结构之间的关系要能够辨析清楚： 　　(1)“That is why...”与“That is the reason why...”同义, 只不过从语法结构上讲, “That is the reason why...”中why引导的是—个定语从句, 将其中的the reason去掉则与“That is why...”结构一样, 例如： 　　That is (the reason) why I cannot agree. 这就是我不能同意的理由. 　　(2)“That is because...”句型中从属连词because引导的名词性从句在此作表语, 这也是个常用句型, 意为“这就是为什么……/因为……”.“That is because...”与“That is why...”之间的不同在于“That is because...”指原因或理由, “That is why...”则指由于各种原因所造成的后果, 例如： 　　He did not see the film last night. That is because he had to help his little sister with her homework.昨天晚上他没有去看电影, 那是因为他得帮助他的妹妹做作业.(第一句话说明结果, 第二句话说明原因) 　　He had seen the film before. That is why he did not see it last night.他以前曾看过那部电影, 因此他昨天晚上没有去看.(第一句话说明原因, 第二句话说明结果)

主语部分为句子就是主语从句，表语部分为句子就是表语从句。也就是说，主语，表语部分的句子就是相应的从句。

说白了，充当表语的句子就是表语从句，充当主语的句子就是主语从句