大学英语语法存在句

存在句
存在句(existential sentence)传递新信息，引出新话题。

这种句型之所以要用there做形式主语而把实义主语置于动词之后正是为了让这种实义主语成为信息中心，以达到引出新话题的目的。

1.在句的结构特征
存在句是以there作为引导词或形式主语，谓语动词通常是助动词be或其他含有存在意义的动词的一定形式；动词之后跟有通常叫做实义主语或真主语的名词词组；实义主语之后通常跟有地点状语，有时还带时间状语。

因此，存在句的结构模式是：There+be+NP+Locative Expression(+Temporal Expression).
1)存在句的引导词
存在句的引导词there在句子中居于主语的位置，实义主语虽然是随后的名词词组，但there起形式主语的作用，在疑问句中，它和操作词倒装：
Are there any people in the hall?
There is a typewriter in the room, isn’t there?
在非正式语体中，引导词there 还决定主谓一致关系，既动词的单，复数形式间或并不取决于随后的名词词组而取决于引导词there.例如：
Ther e’s some people in the waiting room.(非正式语体)
There are some people in the waiting room.
要区别存在句的引导词there 和句首状语there ,前者不重读，后者须重读。

2）存在句的实义主语
在存在句中作实义主语的名词词组通常是非确定特指，即通常带有不定冠词，零冠词及其其他表示非确定意义的限定词，如some, any, no, several, many, much, more, a few, a little, less, another, a lot of , plenty of, a large number of , enough, 以及基数词等，而且名词中心词还可以带有前置，后置修饰词。

例如：
There is a cherry tree in my garden.
There are roses in the flower beds.
There’s no one in the house, is there?
There is still a lot of work to be done before the house in ready for occupation.
There are many people still with too low a standard of living.
There are fifteen students in my class.
Is there any cheese in the larder?
作为存在句实义主语的名词词组也可以由some-, any-, no- 的合成词构成。

例如：
There’s something that you don’t know.
There is nothing more to do.
Is there anyone coming to dinner?
由上述猪咧可以看出，存在句的实义主语一般都是非确定特指，正因为如此，前面所说的基本句型凡带有非确定特指的名词词组，一般都可以用there-存在句予以转换。

例如：No one was waiting.
There was no one waiting.
Something must be wrong.
There must be something wrong.
Plenty of people are getting promotion
There are plenty of people getting promotion.
Something is causing her distress. There’s something causing her distress.
Two bulldozers have been knocking the place flat.
There have been two bulldozers knocking the place flat.
3）存在句的谓语动词
存在句的谓语动词主要是动词be 的某种形式，可以是限定形式。

也可以是非限定形式。

先讲be的限定形式。

限定形式可以是be的一般现在时，一般过去时，现在完成体或过去完成体。

例如：
There’s a train due to arrive.
There have been many such accidents.
也可以是表示预见，可能，必然或过去习惯存在的情态助动词（包括完成体形式）。

例如：
There ‘ll be a huge crowd at the game, won’t there?
There can be very little doubt about his guilt.
Mustn’t there be another reason for his behavior?
There used to be a church round the corner.
A:Was there an answer to my telegram?
B:John says there must have been one.
There can’t have been much traffic so late at night.
也可以使半动词+不定式（很少用完成体形式）。

例如：
There’s going to be a storm.
There’s to be an investigation.
There appears to be no doubt about it.
以上三类动词形式是限定形式的主语。

除be外，某些表示存在概念的不及物动词如exist, remain, happen, occur, come, arise, stand, lie, live等，也能用于there-存在句。

例如：
There arose in his imagination visions of a world empire.
If ever again there happens an accident like that, we’ll have only ourselves to blame.
如果地点状语前移便可省略there. 例如：
Behind the house (there) lies a river.
In front of the carriage (there) rode two men in uniform.
2. 存句的非限定形式
存在句的非限定形式是there to be 和there being结构。

这两种结构在用法上有相同点。

1）作介词补足成分
两种结构都可以作介词补足成分。

如果介词是for, 便只能用there to be 结构。

例如：
For there to be so few people in the streets was unusual.
===It was unusual for there to be so few people in the street.
也能用在不及物动词+for之后：
They planned for there to be another meeting.
如果介词不是for, 则要用there being 结构。

例如：
John was relying on there being another opportunity.
2)作宾语
作宾语时，通常用there to be 结构。

例如：
Members like there to be plenty of choice.
能这样用的及物动词为数有限，常见的有expect, mean, intend, want, like, prefer, hate等。

2）作主语和状语
There being 结构还能用作主语和状语。

例如：
There being a bus stop so near the house is a great advantage. There having been no rain, the ground was dry.
存在句的限定形式与非限定形式之间可以相互转换。

例如：It was unusual for there to be so few people in the streets.
----- It was unusual that there were so few people in the streets. 有时限定形式与非限定形式还可以结合使用。

例如：
It is said that there are troops on the frontier.
---There are said to be troops on the frontier.。