2017英語等級考試pets5級考試重點語法精講（二）
2017英語等級考試pets5級考試重點語法精講（二）
【名詞性從句】
概念
在句子中起名詞作用的句子叫名詞從句 (Noun Clauses)。 名詞從句的功能相當(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，名詞從句又可分別稱為主語從句、賓語從句、表語從句和同位語從句。
引導(dǎo)名詞性從句的連接詞
引導(dǎo)名詞性從句的連接詞可分為三類：
連接詞：that、whether、if不充當(dāng)從句的任何成分)
連接代詞：what、whatever、who、whoever、whom、whose、which.
連接副詞：when、where、how、why
不可省略的連詞
1. 介詞后的連詞
2. 引導(dǎo)主語從句和同位語從句的連詞不可省略。
That she was chosen made us very happy.
We heard the news that our team had won.
比較：whether與if 均為“是否”的意思。 但在下列情況下，whether不能被if 取代：
1. whether引導(dǎo)主語從句并在句首
2. 引導(dǎo)表語從句
3. whether從句作介詞賓語
4. 從句后有“or not”
Whether he will come is not clear.
大部分連接詞引導(dǎo)的主語從句都可以置于句末，用it充當(dāng)形式主語。
It is not important who will go.
It is still unknown which team will win the match.
名詞性that-從句
1)由從屬連詞that引導(dǎo)的從句叫做名詞性that-從句。That只起連接主句和從句的作用，在從句中不擔(dān)任任何成分，本身也沒有詞義。名詞性that-從句在句中能充當(dāng)主語、賓語、表語、同位語和形容詞賓語，例如：
主語：That he is still alive is sheer luck.他還活著全靠運氣。
賓語：John said that he was leaving for London on Wednesday.約翰說他星期三要到倫敦去。
表語：The fact is that he has not been seen recently.事實是近來誰也沒有見過他。
同位語：The fact that he has not been seen recently disturbs everyone in his office.
近來誰也沒有見過他，這一事實令辦公室所有的人不安。
形容詞賓語：I am glad that you are satisfied with your job.
你對工作滿意我感到很高興。
2)That-從句作主語通常用it作先行詞，而將that-從句置于句末，例如：
It is quite clear that the whole project is doomed to failure.很清楚，整個計劃注定要失敗。
It’s a pity that you should have to leave.你非走不可真是件憾事。
用it作形式主語的that-從句有以下四種不同的搭配關(guān)系：
a.It + be +形容詞+ that-從句
It is necessary that... 有必要……
It is important that... 重要的是……
It is obvious that... 很明顯……
b. It + be + -ed分詞+ that-從句
It is believed that... 人們相信……
It is known to all that... 從所周知……
It has been decided that... 已決定……
c. It + be +名詞+ that-從句
It is common knowledge that... ……是常識
It is a surprise that... 令人驚奇的是……
It is a fact that... 事實是……
d. It +不及物動詞+ that-分句
It appears that... 似乎……
It happens that... 碰巧……
It occurred to me that... 我突然想起……
名詞性wh-從句
1)由wh-詞引導(dǎo)的名詞從句叫做名詞性wh-從句。Wh-詞包括who、whom、whose、whoever、what、whatever、which、whichever等連接代詞和where、when、how、why等連接副詞。
Wh-從句的語法功能除了和that-從句一樣外，還可充當(dāng)介詞賓語、賓語補語和間接賓語等，例如：
主語： How the book will sell depends on its author.書銷售如何取決于作者本人。
直接賓語：In one’s own home one can do what one likes.在自己家里可以隨心所欲。
