同位語(yǔ)從句指的是在復(fù)合句中充當(dāng)同位語(yǔ)的從句，可以對(duì)其前面的抽象名詞做解釋說(shuō)明，屬于名詞性從句的范疇。同位語(yǔ)從句的引導(dǎo)詞為"that"，無(wú)含義，不充當(dāng)成分，不可省略。

1. that引導(dǎo)同位語(yǔ)從句。

在下列名詞后可用that引導(dǎo)同位語(yǔ)從句answer, belief, doubt, fact, hope, idea, information, knowledge, law, news, opinion, plan, suggestion, thought, truth等。

I had no idea that you were here.

The story goes that William killed his wife.

He always works hard in spite of the fact that he is not in good health.

Suddenly the thought came to me that he would go blind.

注意：

①位語(yǔ)從句引導(dǎo)詞that無(wú)含義，不充當(dāng)成分，不可省略。

②同位語(yǔ)從句與其說(shuō)明的名詞或代詞為同一內(nèi)容，故可以用is把前邊的中心詞和從句連接成一個(gè)句子。

③同位語(yǔ)從句前一般沒有逗號(hào)。

that引導(dǎo)同位語(yǔ)從句與引導(dǎo)定語(yǔ)從句的區(qū)別：that引導(dǎo)同位語(yǔ)從句時(shí)只起連接作用，不充當(dāng)任何成分;that引導(dǎo)定語(yǔ)從句時(shí)，在從句中要作成分，如主語(yǔ)、賓語(yǔ)等。

①He told me the news that our team won.(that引導(dǎo)同位語(yǔ)從句)

②The news that / which he told me was very exciting.(that引導(dǎo)定語(yǔ)從句，在從句中作賓語(yǔ))

2. 在no idea, question, problem等后可用wh-疑問詞引導(dǎo)同位語(yǔ)從句，if不引導(dǎo)同位語(yǔ)從句。

I have no idea where he has gone.

I have no idea what he said.

3. 辨析：引導(dǎo)名詞性從句時(shí)what與whatever, who與whoever的區(qū)別：

what 與whatever：

What you want has been sent here.(what = the thing(s) that/all that/anything that特指)

Whatever you want makes no difference to me.(whatever = anything that泛指)

What caused the accident was a broken bottle.(特指)

Whatever caused the accident has not yet been found.(泛指)

who 與whoever：

Who will go to Beijing on business has not been decided.(who表疑問，表示“誰(shuí)”，“哪一個(gè)”)

Whoever breaks the law should be punished.(whoever = anyone who，表示“無(wú)論哪個(gè)人”)

4. 同位語(yǔ)從句注意與定語(yǔ)從句區(qū)別

同位語(yǔ)從句對(duì)前一名詞做補(bǔ)充說(shuō)明，在從句中無(wú)語(yǔ)法位置，而定語(yǔ)從句所修飾詞在從句中占一語(yǔ)法位置如：

The idea that one can do the work without thinking is wrong.(同位idea在從句中無(wú)位置，而從句只是具體說(shuō)明idea的內(nèi)容)

The idea that you put forward at the meeting is wrong.(定語(yǔ)從句，idea做put forward 的賓語(yǔ))