1 any用于否定句和疑问句，表示不确切的少量，意为“一些”，相当于肯定句中表示少量意义的some。请对比肯定句中的some和否定、疑问句中的any:

There is some water in the bottle.

There is not any water int the bottle.

Is there any water in the bottle?

There are some students in the classroom.

There are not any students in the classroom.

Are there any students in the classroom?

不能说Is there any student in the classroom.

而应说Is there a student in the classroom.

2 在肯定句中，any并非“一些”的意思，而是表示三个或三个以上的总体中的“任何一个”。相当于either表示二者中的任何一个的用法。后接单数可数名词。

Any child who breaks the rules will be punished. 

Always check the details carefully before you sign any written agreement. 

If I can help in any way, let me know.

Tom is taller than any other student in his class.

不能说He is taller than any other students in his class.

但是，any可以后接数词，再接复数名词。例如，any two/three etc.+复数名词：

He and Jess are as different, complexionwise, as any two people can be.

For a while, they really were like any two brothers. 

网友可提供例外情况，我们进行分析。