【導(dǎo)語】高三的日子是苦的，有剛?cè)敫呷龝r(shí)的迷茫和壓抑，有成績失意時(shí)的沉默不語，有晚上奮戰(zhàn)到一兩點(diǎn)的精神肉體雙重壓力，也有在清晨凜冽的寒風(fēng)中上學(xué)的艱苦經(jīng)歷。在奮筆疾書中得到知識(shí)的快樂，也是一種在巨大壓力下顯得茫然無助的痛苦。逍遙右腦為你整理《高三英語必修四知識(shí)點(diǎn)歸納：名詞性從句的辨別方法》希望對(duì)你有幫助！
主語從句
主語從句是在復(fù)合句中充當(dāng)主語的從句，通常放在主句謂語動(dòng)詞之前或由形式主語it代替，而本身放在句子末尾。
1. It 作形式主語和it引導(dǎo)強(qiáng)調(diào)句的比較。
It 作形式主語代替主語從句，主要是為了平衡句子結(jié)構(gòu)，主語從句的連接詞沒有變化。而it引導(dǎo)的強(qiáng)調(diào)句則是對(duì)句子某一部分進(jìn)行強(qiáng)調(diào)，無論強(qiáng)調(diào)的是什么成分，都可用連詞that。被強(qiáng)調(diào)部分指人是也可用who/whom。
例如：
It is a pity that you didn’t go to see the film.
It doesn’t interest me whether you succeed or not.
It is in the morning that the murder took place.
It is John that broke the window.
2. 用it 作形式主語的結(jié)構(gòu)。
(1) It is +名詞+從句
It is a fact that … 事實(shí)是…
It is an honor that …非常榮幸
It is common knowledge that …是常識(shí)
(2) it is +形容詞+從句
It is natural that… 很自然…
It is strange that… 奇怪的是…
(3) it is +不及物動(dòng)詞+從句
It seems that… 似乎…
It happened that… 碰巧…
(4) it +過去分詞+從句
It is reported that… 據(jù)報(bào)道…
It has been proved that… 已證實(shí)…
3. 主語從句不可位于句首的五種情況。
(1) if 引導(dǎo)的主語從句不可居于復(fù)合句句首。
(2) It is said ， (reported) …結(jié)構(gòu)中的主語從句不可提前。
例如：
It is said that President Jingo will visit our school next week. (right)
That President Jiang will visit our school next week is said. (wrong)
(3) It happens…， It occurs… 結(jié)構(gòu)中的主語從句不可提前。
例如：
It occurred to him that he failed in the examination. (right)
That he failed in the examination occurred to him. (wrong)
(4) It doesn’t matter how/whether …結(jié)構(gòu)中的主語從句不可提前。
例如：
It doesn’t matter whether he is wrong or not. (right)
Whether he is wrong or not doesn’t matter. (wrong)
(5) 含主語從句的復(fù)合句是疑問句時(shí)，主語從句不可提前。
例如：
Is it likely that it will rain in the evening? (right)
Is that will rain in the evening likely? (wrong)
4. What 與that 在引導(dǎo)主語從句時(shí)的區(qū)別。
What 引導(dǎo)主語從句時(shí)在句時(shí)在從句中充當(dāng)句子成分，如主語.賓語.表語，而that 則不然。
例如：
1) What you said yesterday is right.
2) That she is still alive is a consolation.
賓語從句
賓語從句就是在復(fù)合句中作賓語的名詞性從句，通常放在主句謂語動(dòng)詞(及物動(dòng)詞)或介詞之后。
1. 作動(dòng)詞的賓語。
(1) 由that引導(dǎo)的賓語從句(that 通�？梢允÷�)
例如：
I heard that be joined the army.
(2) 由what， whether (if) 引導(dǎo)的賓語從句
例如：
1) She did not know what had happened.
2) I wonder whether you can change this note for me.
(3) 動(dòng)詞+間接賓語+賓語從句
例如：
She told me that she would accept my invitation.
2. 作介詞的賓語。
例如：
Our success depends upon how well we can cooperate with one another.
3. 作形容詞的賓語。
例如：
I am afraid (that) I’ve made a mistake.
That 引導(dǎo)的從句常跟在下列形容詞后作賓語：
Anxious， aware， certain， confident， convinced， determined， glad， proud， surprised， worried， sorry， thankful， ashamed， disappointed， annoyed， pleased， hurt， satisfied， content 等。也可以將此類詞后的that 從句的看作原因狀語從句。
4. It 可以作為形式賓語。
It 不僅可以作為形式主語，還可以作為形式賓語而真正的賓語that 從句則放在句尾，特別是在帶復(fù)合賓語的句子中。
例如：
We heard it that she would get married next month..
5. 后邊不能直接跟that 從句的動(dòng)詞。
這類動(dòng)詞有Allow， refuse， let， like， cause， force， admire， condemn， celebrate， dislike， love， help， take， forgive等。這類詞后可以用不定式或動(dòng)名詞作賓語，但不可以用that引導(dǎo)的賓語從句。
例如：
I admire their winning the match. (right)
I admire that they won the match. (wrong)
6. 不可用that從句作直接賓語的動(dòng)詞。
有些動(dòng)詞不可用于“動(dòng)詞+間接賓語+that從句“結(jié)構(gòu)中，常見的有Envy， order， accuse， refuse， impress， forgive， blame， denounce， advise， congratulate等。
例如：
He impressed the manager as an honest man. (right)
He impressed the manager that he was an honest man. (wrong)
7. 否定的轉(zhuǎn)移
若主句謂語動(dòng)詞為Think， consider， wuppose， believe， expect， fancy， guess， imagine等，其后的賓語從句若含有否定意義，一般要把否定詞轉(zhuǎn)移到主句謂語上，從句謂語用肯定式。
例如：
I don’t think this dress fits you well.(我認(rèn)為這件衣服不適合你穿。)
表語從句
表語從句在復(fù)合句中作表語的名詞性從句，放在系動(dòng)詞之后，一般結(jié)構(gòu)是“主語+連系動(dòng)詞+表語從句”。可以接表語從句的連系動(dòng)詞有be， look， remain， seem等。引導(dǎo)表語從句的that常可省略。另外，常用的還有the reason is that… 和It is because 等結(jié)構(gòu)。
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.
同位語從句
同位語從句就是在復(fù)合句中作名詞的同位語的名詞性從句。
1. 同位語從句的功能。
同位語從句對(duì)于名詞進(jìn)一步解釋，說明名詞的具體內(nèi)容，一般由that引導(dǎo)。
例如：
1) The king’s decision that the prisoner would be set free surprised all the people.
2) The order that all the soldiers should stay still is given by the general.
2. 同位語在句子中的位置。
同位語從句有時(shí)可以不緊跟在它所說明的名詞后面，而是被別的詞隔開。
例如：
He got the news from Mary that the sports meeting was put off.
3. 同位語從句與定語從句的區(qū)別。
(1) 定語從句中的that既代替先行詞，同時(shí)以在從句中作某個(gè)成分(主語或賓語)，而同位語從句中的that是連詞，只起連接主句與從句的作用，不充當(dāng)句中任何成分。
(2) 定語從句是形容詞性的，其功能是修飾先行詞，對(duì)先行詞加以限定，描述定的性質(zhì)或特征;同位語從句是名詞性的，其功能是對(duì)名詞進(jìn)行補(bǔ)充說明。例如：
1) The news that he told me is that Tom would go abroad next year.(他告訴我的消息是湯姆明年將出國。)(第一個(gè)that引導(dǎo)的從句是定語從句，that在從句中作賓語)
2)The news that Tom would go abroad is told by him.(湯姆將出國的消息是他講的。)(同位語從句，that在句中不作任何成分) 。
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