名詞性從句的用法

名詞性從句包括主語從句#65380;表語從句#65380;賓語從句和同位語從句#65377;引導名詞性從句的連詞有:who；whom；whose；what；which；when；where；why；how；that；if；whether；whatever；whenever；wherever；however 等#65377;

名詞性從句注意事項:從句的語序為陳述句；連詞that不充當任何成分；what總是要充當主語#65380;表語#65380;賓語等#65377;

if和whether的區別:if引導賓語從句和條件狀語從句；whether引導主語從句#65380;表語從句#65380;賓語從句和同位語從句#65377;

(一)主語從句

用作主語的從句，叫主語從句#65377;主語從句可以直接放在句首；也可用it作形式主語，而將從句放在句末#65377;

常見的用it作形式主語的復合結構:

It is + 名詞 + that從句；It is a fact(a pity，a shame，no wonder，good news...)that...

It is + 形容詞 + that從句；It is necessary(strange，important，wonderful，possible，likely，...)that... 這類句中謂語動詞多為(should) + 動詞原形#65377;

It is + 過去分詞 + that 從句；It is said(reported，decided，believed，...)that...

It + 不及物動詞 + that 從句；It seems(happened，doesn’t matter，has turned out，...)that...

What you need is more practice. 你需要的是更多的練習#65377;(what在從句中作need的賓語)

What is hard is to do good all one’s life and never do anything bad. 難的是人的一生都做好事#65380;從不做壞事#65377;(what在從句中作主語)

What he will be in the future is known to us. 我們知道他未來會干什么#65377;(what在從句中作be的表語)

Who will go makes no difference. 誰去都一樣#65377;

How this happened is not clear. 這件事是怎樣發生的還不清楚#65377;

Why he did that wasn’t quite clear. 他為什么那樣做相當不清楚#65377;

Whether she will join us won’t make too much difference. 她是否加入我們沒多大區別#65377;(此處不能用if)

Whoever comes will be welcome. 不管誰來都受歡迎#65377;(whoever在名詞性從句中相當于anyone who)

Whatever she did was right. 不管她做什么都是正確的#65377;(whatever在名詞性從句中相當于anything that)

It is possible that I may not be able to come. 可能我不能來了#65377;(it是形式主語，真正的主語是that I may not...部分)

It doesn’t seem likely that she will be here. 看來她不會來這了#65377;

Isn’t it strange that he should have left without telling us?他沒有告訴我們就離開了，難道不奇怪嗎?

It occurred to me that he had forgotten to take his notebook with him. 我想起來，他忘記隨身帶筆記本了#65377;

That we need more equipment is quite obvious. 很明顯，我們需要更多的設備#65377;

Has it been announced when the planes are to take off?已經宣布飛機什么時候起飛了嗎?

(二)表語從句

用作表語的從句叫表語從句#65377;它位于連系動詞(如be，seem，remain 等后)#65377;

The question is whether we should accept their invitation. 問題是我們是否應當接受他們的邀請#65377;

The city is no longer what it used to be. 這個城市不再是曾經的樣子#65377;

This is why we put off the meeting.(why表結果)這就是為什么我們推遲了會議#65377;

That is because he was ill.(because表原因)那是因為他生病了#65377;

The reason for his absence was that he was ill.(此處不能用because代替that . 句型:The reason... is that...)他缺席的原因是他生病了#65377;

as if 引導的表語從句有時可用虛擬語氣，表示可能性小#65377;

He acted as if he hadn’t eaten for a long time.

表示建議#65380;命令#65380;要求一類的表語從句要用虛擬語氣:

My suggestion is that you should practise reading English every day.

(三)賓語從句

作賓語的從句叫賓語從句#65377;

作動詞的賓語:

He doesn’t know where the post office is. 他不知道郵局在哪里#65377;

在動詞suggest，order，demand，require等表示建議#65380;命令#65380;要求的賓語從句要用虛擬語氣(賓語從句的謂語用should + 動詞原形，should 可省略#65377;)

I suggested that you(should)start right now. 我建議你馬上開始#65377;

如果賓語從句后有賓語補足語，要用形式賓語it，而將從句放到補足語后面#65377;

I thought it strange that he didn’t pass the exam. 我覺得他沒通過考試很奇怪#65377;

在think，believe，suppose，expect等動詞后的賓語從句中，如果從句謂語是否定含義，則不用否定形式，而將主句謂語動詞think等變為否定形式#65377;

I don’t think you are right. 我想你是不對的#65377;

He doesn’t know where the post office is. 他不知道郵局在哪里#65377;

在think，believe，imagine，suppose，guess，hope等動詞以及I’m afraid等后，可用so代替一個肯定的賓語從句，還可用not代替一個否定的賓語從句:

Do you believe it will clear up?你認為天會放晴嗎?

I believe so.(I don’t believe so. /I believe not.)我認為會#65377;(我認為不會#65377;)

(2)作介詞的賓語:

Did she say anything about how we should do the work?他有沒有說我們應當怎樣做這個工作?

That引導的賓語從句只有在except，in，but，besides等少數介詞后偶爾可能用到#65377;

Your article is good except that it is too long. 除了太長外，你的論文很好#65377;

有時在介詞和其賓語從句的中間加形式賓語it#65377;

I’ll see to it that everything is ready. 我將負責把一切準備好#65377;

(3)作形容詞的賓語:

I’m afraid that I have made a mistake.

if和whether引導賓語從句的區別，即用whether不用if的情況有:

作介詞賓語，用于whether + to do#65380;whether or not和用作discuss的賓語等#65377;

It depends on whether it is fine. 要看天氣是否晴朗#65377;

I’m not sure whether to leave this afternoon. 我不敢肯定今天下午是不是要出發#65377;

He can not decide whether or not to take the exam. 他不能決定參不參加考試#65377;

We are discussing whether we will hold a meeting this weekend. 我們在討論這個周末是否要舉行一場會議#65377;

doubt用于肯定句中，賓語從句可以用if或whether引導#65377;

I doubt if(whether)you will come for a visit tomorrow. 我懷疑你明天是否要來拜訪一下#65377;

doubt用于否定句或疑問句中，賓語從句用that引導#65377;

He doesn’t doubt that his mother will give him a ride home for sure. 他很確信他的媽媽會開車帶他回家#65377;

(四)同位語從句

同位語從句跟在一個名詞后(如fact，idea，news，hope，belief，thought，doubt，proof，belief等)，對其作進一步解釋#65377;

I have no idea that you were here. 我不知道你在這里#65377;

He can’t answer the question how he got the money. 他不能回答他是如何拿到那筆錢的#65377;

同位語從句和定語從句的區別:

從意義上講，前者對名詞加以解釋說明，后者對名詞進行修飾限定#65377;從結構上講，前者由連接詞引導，后者由關系詞引導#65377;從內涵上講，前者所說明的名詞與從句沒有邏輯關系，that不可省略#65377;后者所限定的名詞是從句邏輯上的主語#65380;賓語#65380;表語#65380;定語#65380;狀語等#65377;當被限定的名詞是從句邏輯上的賓語時，that 可省略#65377;

The news that they won the match is true. 他們贏得比賽的消息是真的#65377;(同位語從句，news和從句沒有邏輯關系，that不可省略)

The news that you told us yesterday is true. 你昨天告訴我的那個消息是真的#65377;(定語從句，news 是told 的邏輯賓語，that可省略)

編輯/梁宇清