在學(xué)習(xí)名詞性從句之前，我們首先要明白一個(gè)詞：復(fù)合句
什么叫復(fù)合句
? ? ?由一個(gè)主句和一個(gè)或一個(gè)以上的從句構(gòu)成的句子叫復(fù)合句。在復(fù)合句中主句是全句的主體，從句是全句的一個(gè)成分，不能獨(dú)立。從句通常是用關(guān)聯(lián)詞來(lái)引導(dǎo)的。在這里關(guān)聯(lián)詞還起聯(lián)系從句和主句的作用。?
一、從句的種類(lèi)：
? ? ?主語(yǔ)從句、賓語(yǔ)從句、表語(yǔ)從句、同位語(yǔ)從句，定語(yǔ)從句和狀語(yǔ)從句
二、名詞性從句的連接詞
1. 單純連詞
在從句中不補(bǔ)充當(dāng)任何成分，只起到連接從句的功能。
that 沒(méi)有實(shí)際意義，而whether/ if 在句子中表示“是否” 的意義。
Eg : That the prices of rice will go up is certain. (that引導(dǎo)主語(yǔ)從句，補(bǔ)充當(dāng)任何成分)
? ? ? ?He asked if I could come to see him this weekend.
? ? ?形式主語(yǔ)it 代替主語(yǔ)從句位于句首時(shí)，常見(jiàn)的幾種情況：
? ? ?①?It + adj +that 從句(大多數(shù)情況下that從句后用should+動(dòng)詞原形)
? ? ? Adj: necessary ?right ?clear ?unlikely ?strange ?obvious ?natural ?important
? ? ? Eg: It is necessary to learn English well.
? ? ? ②?It +系動(dòng)詞+名詞+that 從句
? ? ? Non: a pity ?an honor ?good news ?a wonder ?a fact ?no wonder ?no surpeise
? ? ? Eg: It is a fact that you are a good boy.
? ? ? ③ It +be + 過(guò)去分詞+that從句
? ? ? 過(guò)去分詞：said / heard/ reported/ told/ decided/suggested/thought/considered/ hoped/ announced?
? ? ? Eg: It is announced that the plan has been canceled.
? ? ?注意：
? ? ?It + be+ suggested/ advised/ ordered/ requested/ insisted/ demand+ that從句， that從句要用should +動(dòng)詞原形，should可以省略。
? ? ?Eg: It is suggested that you (should ) spend more time in studying English .
? ? ?當(dāng)suggest表示“表明”時(shí)，不可以用虛擬語(yǔ)氣
? ? ?Eg: It suggests that you are an honest boy.
? ? ?Insist 表示“堅(jiān)持某種說(shuō)法（事情已經(jīng)發(fā)生過(guò)了）”，不用虛擬語(yǔ)氣。
? ? ?表示“堅(jiān)持要做（事情沒(méi)有發(fā)生）”，要用虛擬語(yǔ)氣。
? ? ?Eg: she insisted that I have never done such thing .
? ? ? ? ? ?She insisted that I study abroad.
? ? ?④It +動(dòng)詞（+賓語(yǔ)或狀語(yǔ)）+that 從句
? ? ?動(dòng)詞如： appear(顯得)/ happen(碰巧)/ matter(重要)/ occur(出現(xiàn))/ turn out(結(jié)果是)
? ? ?Eg: It happened to me that I was away when he came.主語(yǔ)從句不可位于句首的五種情況：
? ? ?注意：
? ? ?（1）if 引導(dǎo)的主語(yǔ)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(yǔ)從句不可提前。
? ? ? ?正確表達(dá)：It is said that President Jiang will visit our school next week.
? ? ? ?錯(cuò)誤表達(dá)：That President Jiang will visit our school next week is said.
? ? ?（3）It happens/occurs?結(jié)構(gòu)中的主語(yǔ)從句不可提前。
? ? ? ?正確表達(dá)：It occurred to him that he failed in the examination.
? ? ? 錯(cuò)誤表達(dá)：That he failed in the examination occurred to him.
? ? ?（4）It doesn’t matter how/whether ?結(jié)構(gòu)中的主語(yǔ)從句不可提前。
? ? ? ?正確表達(dá)：It doesn’t matter whether he is wrong or not.
? ? ? ?錯(cuò)誤表達(dá)：Whether he is wrong or not doesn’t matter.
? ? ?（5）含主語(yǔ)從句的復(fù)合句是疑問(wèn)句時(shí)，主語(yǔ)從句不可提前。
? ? ? ?正確表達(dá)：Is it likely that it will rain in the evening?
? ? ? 錯(cuò)誤表達(dá)：Is that will rain in the evening likely?