英語語法大全-20. 連詞
20. 連詞
連詞是一種虛詞， 它不能獨立擔任句子成分而只起連接詞與詞，短語與短語以及句與句的作用。連詞主要可分為兩類：并列連詞和從屬連詞。并列連詞用來連接平行的詞、詞組和分句。如：and, but, or, nor, so, therefore, yet, however, for, hence, as well as, both…and, not only…but also, either…or, neither…nor, (and)then等等。20.1 并列連詞與并列結構
并列連詞引導兩個并列的句子。1) and 與or
判斷改錯：
(錯) They sat down and talk about something.
(錯) They started to dance and sang.
(錯) I saw two men sitting behind and whisper there.
(對) They sat down and talked about something.
(對) They started to dance and sing.
(對)I saw two men sitting behind and whispering there.
解析：
第一句： and 連接兩個并列的謂語，所以 talk 應改為 talked。
第二句：and 連接兩個并列的動詞不定式，第二個不定式往往省略to，因此sang 應改為 sing。
第三句：and 連接感觀動詞saw 后面的用作的賓補的兩個并列分詞結構，因此whisper應改為whispering。
注意：and 還可以和祈使句或名詞詞組連用表示條件。（or也有此用法）
Make up your mind, and you'll get the chance.
= If you make up your mind, you'll get the chance.
One more effort, and you'll succeed.
= If you make one more effort, you'll succeed.
2) both …and 兩者都
She plays (both) the piano and the guitar.
3) not only…but (also), as well as不但…而且）
She plays not only the piano, but (also) the guitar.
注意： not only… but also 關聯(lián)兩個分句時，一個分句因有否定詞not 而必須倒裝。
Not only does he like reading stories, but also he can even write some.
4) neithe…nor 意思為"既不……也不……"謂語動詞采用就近原則，與nor后的詞保持一致。
Neither you nor he is to blame.
20.2 比較and和or
1) 并列結構中，or通常用于否定句，and用于肯定句。2) 但有時and 也可用于否定句。請注意其不同特點：
There is no air or water in the moon.
There is no air and no water on the moon.
在否定中并列結構用or 連接，但含有兩個否定詞的句子實際被看作是肯定結構，因此要用and。
典型例題
---I don't like chicken ___ fish.
---I don't like chicken, ___ I like fish very much.
A. and； and B. and； but C. or； but D. or；and
答案C。否定句中表并列用or, but 表轉(zhuǎn)折。
判斷改錯：
(錯) We will die without air and water.
(錯) We can't live without air or water.
(對) We will die without air or water.
(對) We can't live without air and water.
20.3 表示選擇的并列結構
1) or 意思為"否則"。I must work hard, or I'll fail in the exam.
2) either…or 意思為"或者……或者……"。注意謂語動詞采用就近原則。
Either you or I am right.
20.4 表示轉(zhuǎn)折或?qū)Ρ?
1) but表示轉(zhuǎn)折，while表示對比。Some people love cats, while others hate them.
典型例題
--- Would you like to come to dinner tonight?
--- I'd like to, ___ I'm too busy.
A. and B. so C. as D. but
答案D。but與前面形成轉(zhuǎn)折，符合語意。而表并列的and， 結果的so，原因的as都不符合句意。
2) not…but… 意思為"不是……而是……"
not 和but 后面的用詞要遵循一致原則。
They were not the bones of an animal, but (the bones) of a human being.
20.5 表原因關系
1) for判斷改錯：
(錯) For he is ill, he is absent today.
(對) He is absent today, for he is ill.
for是并列連詞，不能置于含兩個并列分句的句子的句首，只能將其放在兩個分句中間。
2) so, therefore
He hurt his leg, so he couldn't play in the game.
注意：
a. 兩個并列連詞不能連用，但therefore, then, yet.可以和并列連詞連用。
You can watch TV, and or you can go to bed.
He hurt his leg, and so / and therefore he couldn't play in the game.
b. although… yet…，但although不與 but連用。
(錯) Although he was weak, but he tried his best to do the work..
(對) Although he was weak, yet he tried his best to do the work.
20.6 比較so和 such
其規(guī)律由so與such的不同詞性決定。such 是形容詞，修飾名詞或名詞詞組，so是副詞，只能修飾形容詞或副詞。so 還可與表示數(shù)量的形容詞many，few，much， little連用，形成固定搭配。
so + adj. such + a(n) + n.
so + adj. + a(n) + n. such + n. (pl.)
so + adj. + n. (pl.) such +n. (pl.)
so + adj. + n. [不可數(shù)] such +n. [不可數(shù)]
so foolish such a fool
so nice a flower such a nice flower
so many/ few flowers such nice flowers
so much/little money. such rapid progress
so many people such a lot of people
so many 已成固定搭配，a lot of 雖相當于 many，但 a lot of 為名詞性的，只能用such搭配。
so…that與such…that之間的轉(zhuǎn)換既為 so與such之間的轉(zhuǎn)換。