【高考必考点】
1. 不同连接词的含义；
2. what、which的选择
名词性从句可分为主语从句、表语从句、宾语从句和同位从句。
主语从句 |
做主语，用that，whether，what（＝the thing that）等连接词（原疑问词）引导 |
宾语从句 |
做宾语，用that（可省略），if，whether（or not），what（＝the thing which）等连接词（原疑问词）引导 |
表语从句 |
用that（一般不省略），whether，what（＝the thing which）等连接词（原疑问词）引导 |
同位语从句 |
用that（常用在news，thought，idea等词后），whether等连接词（原疑问词）引导 |
I 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。如：
Who will go is not important.
It doesn’t matter so much whether you will come or not.
That he suddenly fell ill last week made us surprised.
1. It 作形式主语和it引导强调句的比较
It 作形式主语代替主语从句，主要是为了平衡句子结构，主语从句的连接词没有变化。而it引导的强调句则是对句子某一部分进行强原由网调，无论强调原由网的是什么成分，都可用连词that。被强调部分指人是也可用who/whom。例如：
It is a pity that you didn’t go to see thefilm.（主语从句）
It doesn’t interest me whether you succeed or not. （主语从句）
It is in the morning th原由网at the murder took place.（强调句）
It is John that broke the window. （强调句）
2. 用it 作形式主语的结构
句型 |
例子 |
|
1 |
It is ＋名词＋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＋从句 |
It is natural that… 很自然ufLml…/ It is strange that… 奇怪的是… |
3 |
It is ＋不及物动词＋从句 |
It seems that… 似乎…/ It happened that… 碰巧… It appears that… 似乎… |
4 |
It ＋过去分词＋从句 |
It is reported that… 据报道…/ It has been proved that…已证实… It is said that… 据说… |
3. 主语从句不可位于句首的五种情况
情况说明 |
例句 |
|
1 |
if 引导的主语从句不可居于复合句句首。 |
If he will come or not is unknown （误） Whether he will come or not is unknown （正） |
2 |
It is said /reported…结构中的主语从句不可提前 |
It is said that Jiang will visit our school. （正） Jiang will visit our school next week is said. （误） |
3 |
It happens/occurs…结构中的主语从句不可提前 |
It occurred to him that he failed in the examination. （正） That he failed in the examination occurred to him. （误） |
4 |
It doesn’t matter how/whether …结构中的主语从句不可提前 |
It doesn’t matter whether he is wrong or not. （正） Whether he is wrong or not doesn’t matter. （误） |
5 |
含主语从句的复合句是疑问句时，主语从句不可提前 |
Is it likely that it will rain in the evening? （正） Is that will rain in the evening likely? （误） |
II．宾语从句
宾语从句就是在复合句中作宾语的名词性从句，通常放在主句谓语动词(及物动词) 或介词之后。
情况说明 |
例句 |
||
1 |
作动词的宾语 |
由that引导的宾语从句(that 通常可以省略) |
I heard (that) he joined the army. |
由what, whether (if),when, where 等引导的宾语从句 |
She did not know what had happened. I wonder whether you can change this note for me. |
||
动词＋间接宾语＋宾语从句 |
She told me that she would accept my invitation. |
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2 |
作介词的宾语 |
Our success depends upon how well we can cooperate with one another. |
|
3 |
作形容词的宾语 |
I am afraid (that) I’ve 原由网made a mistake. |
|
4 |
it 可以作为形式宾语 |
We heard it that she would get married next month. |
|
5 |
否定的转移（若主句谓语动词为think, consider, suppose, believe, expect, fancy, guess, imagine等，其后的宾语从句若含有否定意义，一般要把否定词转移到主句谓语上，从句谓语用肯定式） |
I don’t think this dress fits you well. 我认为这件衣服不适合你穿。 |
注意：that 引导的从句常跟在下列形容词后作宾语：
anxious,aware, certain, confident, convinced, determined, glad, proud, surprised,worried, sorry, thankful, ashamed, disappointed, annoyed, pleased, hurt,satisfied, content 等。也可以将此类词后的that从句的看作原因状语从句。
III．表语从句
表语从句在复合句中作表语的名词性从句，放在系动词之后，一般结构是“主语＋连系动词＋表语从句”。可以接表语从句的连系动词有be, look,remain, seem等。引导表语从句的that常可省略。另外，常用的还有the reason isthat… 和Itis because 等结构。例如：
1)The question is whether we can make good preparation in such a short time.
2)This is why we can’t get the support of the people.
3)But the fact remains that we are behind the other classes.
4)The reason he is late for school is that he missed the early bus.
IV 同位语从句
同位语从句就是在复合句中作名词的同位语的名词性从句。
情况说明 |
例句 |
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1 |
同位语从句的功能（一般由that引导） |
对于名词进一步解释， |
The king’s decision that the prisoner would be set free surprised all the people. |
说明名词的具体内容， |
The order that all the soldiers should stay still is given by the general. |
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2 |
同位语从句在句子中的位置 |
有时可以不紧跟在它所说明的名词后面，被别的词隔开 |
He got the news from Mary that the sports meeting was put off. |
V whether, if引导名词性从句的区别
情况说明 |
例句 |
|
1 |
在句首引导主语从句时，只能用whether |
Whether we will go camping tomorrow depends on the weather. |
2 |
if不能引导表语从句 |
What the doctor really doubt is whether my mother will recover from the serious disease soon. |
3 |
if 不能引导介词后的宾语从句 |
Everything depends on whether we can make a plan that they will agree to. |
4 |
如果宾语从句是否定句只能用if |
I asked Pave if he hadn’t decided what he would say at the meeting. |
5 |
discuss 后的宾语从句只能用whether引导 |
We discussed whether the medicine will cause side effect. |
注意：doubt 作“怀疑”解，后接宾语从句时，如主句是肯定的，宾语从句用whether 或if 引导；如主句是否定，宾语从句只能用that引导。
(1) I doubt whether/ if he is fit for the job.
(2) I don’t doubt that he can do it very well.
核心语法（一）：
核心语法（二）：
核心语法（三）：
核心语法（四）：数词
核心语法（五）：
核心语法（六）：
核心语法（七）：
