▲简单地说，存在句（即there be 句式）通常针对非确定的人或物，即 there be 后接的名词通常是受 a, some, many, much, a lot of 之类的表示非确定意义的修饰语修饰。如：
There is a telephone in the hall. 大厅有一部电话。
If there is an accident phone 999. 如果发生事故，请拨电话999。
There is some sense in what he says. 他说的话有些道理。
There are some interesting things in your report. 你的报告里有一些有趣的想法。
There is much difficulty in finding his office. 没费什么劲就找到了他的办公室。
There are many more people than we expected. 比我们想象的人要多得多。
▲如果 there be 后接的名词受到特指或确指修饰语的修饰，则通常不是存在句——即句首的 there 为副词，且通常可理解为倒装句。如：
There is the book I want. (=The book I want is there.) 那儿就是我所要的书。
There’s the girl who works with my sister.(= The girl who works with my sister is there.) 那个就是与我妹妹一起工作的女孩子。
▲当然，这说的只是通常的情况。例外的情况也是有的（就不展开分析了），比如：
In the east there is the slightest glimmer of light. 东方闪现出一丝微光。
Do you think there’s the least chance of Labour winning the election? 你认为工党有一丁点儿机会赢得选举吗?
There are the vegetables to peel and the soup to heat. Then there’s the table to lay and the wine to cool. 菜要择，汤要加热。还得摆上餐具，把酒冰镇一下。