在句子中起名詞作用的句子叫名詞性從句 (noun
clauses)。名詞性從句的功能相當(dāng)于名詞詞組，它在復(fù)合句中能擔(dān)任主語、賓語、表語、同位語、介詞賓語等，因此根據(jù)它在句中不同的語法功能，名詞性從句又可分別稱為主語從句、賓語從句、表語從句、同位語從句、介詞賓語從句等。
主語從句在復(fù)合句中用作主語的從句稱為主語從句 (subject
clause)。引導(dǎo)主語從句的關(guān)聯(lián)詞有從屬連詞、疑問代詞、疑問副詞、縮合連接代詞、縮合連接副詞等。如：
That they were in truth sisters was clear from the facial resemblance
between them.
很明顯，她們的確是親姊妹，她們的臉型很相似。(關(guān)聯(lián)詞是從屬連詞that) Who should be responsible for the
senior citizens has been widely discussed in our community.
誰應(yīng)該對老年人負責(zé)這個問題在社區(qū)里被廣泛討論。(關(guān)聯(lián)詞是疑問代詞who) Where we can dispose of the increasing
rubbish is a great headache to many governments.
在哪兒處置日益增多的垃圾對很多政府而言是件頭痛的事。(關(guān)聯(lián)詞是疑問副詞where) Whoever pollutes the environment
should be punished.
不論誰污染環(huán)境都應(yīng)該受到懲罰。(關(guān)聯(lián)詞是縮合連接代詞whoever) Wherever you are is my home—my only
home.
你所在的任何地方就是我的家——我的家。(關(guān)聯(lián)詞是縮合連接副詞wherever)有時可以用it作為形式主語，將真實主語從句置于句末。如：
1. It is probable that the nocturnal trades go way back in the ancestry of
all mammals.
很可能這種夜間的謀生可以追溯至所有哺乳動物的祖先。
2. It should be no surprise then that among mathematicians and architects，
left-handers tend to be more common and there are more left-handed males than
females.
在數(shù)學(xué)家和建筑學(xué)家中，左撇子更常見并且左撇子的男性比女性要多，這并不驚奇。
3. It is reported that millions of people die of water-related disease each
year.
據(jù)報道每年有成千上百萬人死于和水有關(guān)的疾病。
表語從句在復(fù)合句中用作表語的從句稱為表語從句 (predictive
clause)。引導(dǎo)表語從句的關(guān)聯(lián)詞有疑問代詞、疑問副詞、縮合連接代詞、從屬連詞等。如：
The problem is who they can rely on.
問題是他們能依賴誰呢。(關(guān)聯(lián)詞是疑問代詞who) The question is how they have achieved this.
問題是他們是怎樣完成的。(關(guān)聯(lián)詞是疑問副詞how) He looked just as he had looked ten years
before.
他看起來還和十年前一樣。(關(guān)聯(lián)詞是從屬連詞as) Indeed acting as a tourist is one of the defining
characteristics of being ‘modern’ and the popular concept of tourism is that it
is organized within particular places and occurs for regularized periods of
time.
確實作為一個游客是“現(xiàn)代”的定義性特點之一，并且旅游的普遍性觀念是它在某個特定地點組織并且發(fā)生于規(guī)律性的時間段。(關(guān)聯(lián)詞是從屬連詞that)賓語從句在復(fù)合句中用作賓語的從句稱為賓語從句
(object clause)。引導(dǎo)賓語從句的關(guān)聯(lián)詞有從屬連詞、疑問代詞、疑問副詞、縮合連接代詞、縮合連接副詞等。如：
Animal right activists claim that animal tests are cruel， inhumane and
unnecessary.
動物權(quán)益保護聲稱動物實驗很殘忍、沒人道和不必要。(關(guān)聯(lián)詞是從屬連詞that) I know he has succeeded.
我知道他已經(jīng)成功了。(在非正式文體中關(guān)聯(lián)詞that被省去)
