2019高考英語(yǔ)備考 名詞性從句
（1）that的用法。[]
①主語(yǔ)從句、表語(yǔ)從句、同位語(yǔ)從句中用that但不能省略。如：
that they are good at english is known to us all.
the problem is that we don’t have enough money.
she expressed the hope that they would come to china one day.
②賓語(yǔ)從句中的連接詞that有時(shí)可省有時(shí)又不可省，在以下幾種情況中that不能省略：（a）當(dāng)that從句和主句謂語(yǔ)動(dòng)詞之間有插入詞語(yǔ)或者從句主語(yǔ)之間有插入語(yǔ)時(shí)，that不可省略；（b）當(dāng)that 從句與另一名詞性從句并列作賓語(yǔ)時(shí)，that不能省；（c）當(dāng)that作介詞賓語(yǔ)時(shí)，that不可省掉。 如：
he judged that,because he was a child, he did not understand
wine
everyone knew what happened and that she was worried.
the reason lies in that she works harder than the others do.
③that從句作主語(yǔ)和賓語(yǔ) 時(shí)，可以用it 來(lái)替換成以下幾種結(jié)構(gòu)表達(dá)。
(a)it is clear/certain/likely/true/surprising that… （b）it is a pity/shame/g ood idea/no wonder that ...（c）it is said/reported/ believed/known/thought/suggested that … （d）it seems/happens t hat。如：
it happened that i went out last night.
it is said that china will win in the world cup.
④that和what的區(qū)別。
that 引導(dǎo)名詞性從句時(shí)，在主從句中不以當(dāng)任何句子成分，也沒(méi)有任何含義；而what引導(dǎo)名詞性從句時(shí)，在主從句中都要充當(dāng)一定的句子成分，what可以分解成定語(yǔ)從句中的先行詞 + 關(guān)系代詞即常說(shuō)的先行詞 + that。如：
it’s shame that he has made such a mistake. do what he says.
⑤同位語(yǔ)從句與定語(yǔ)從句中that的區(qū)別。
同位語(yǔ)從句中的連詞that只起連接作用，在從句中不擔(dān)當(dāng)任何句子成分；而定語(yǔ)從句中的關(guān)系代詞that在句中做賓語(yǔ)或主語(yǔ)，賓語(yǔ)與先行詞有修飾關(guān)系。如果句子是同位語(yǔ)從句，就應(yīng)用連詞that而不能用which.同位語(yǔ)從句一般放在表具體含義的名詞后解釋名詞的含義或內(nèi)容，如以下名詞：news、fact、suggestion、truth、plan、belief、doubt、possibilit y、idea等，而定語(yǔ)從句只是對(duì)先行詞的限定和修飾。如：
they expressed the hope that they would come to visit china again.(同位語(yǔ) 從句)
the hope she expressed is that they would come to visit china again.（定語(yǔ)從句）
（2）whether和if的用法。
①whether和if在賓語(yǔ)從句中可以互換，但是作介詞賓語(yǔ)時(shí)連接詞一般用whether。如：
it all depends on whether they will come back.
②后面直接跟or not 時(shí)用whether。如：
i didn’t know whether or not he had arrived in wuhan.
③主語(yǔ)從句表語(yǔ)從句中只能用whether。如：
whether the meeting will be put off has not been decided yet.
the question is whether they have so much money.
④whether可以引導(dǎo)同位語(yǔ)從句，用以說(shuō)明前面的名詞的內(nèi)容，if不能。如：
we ought to discuss carefully the question whether we can do
it or not.
⑤whether常與or連用表示一種選擇，if不能這樣用；whether也可與動(dòng)詞不定式連用但if不能。如：