articles - most/most of/ the most of

Are all of the following sentences correct? Is there any difference in their meaning?

• Most birds can fly.


• The most of birds can fly.


• Most of birds can fly.

Answer

Use most to refer to a quantity of an unspecific group. We use most when we are speaking in general and do not have a specific group of people or things in mind:

• 
  

  Most students ask questions.

  
  


• 
  

  All students want A's.

  
  
  


• 
  

  Many students want less homework.

  
  


• 
  

  A few students had to stay for a review session. (some)

  
  


• 
  

  Few students had to stay for a review session. (not many)

  
  

Use most of the X to refer to a quantity of a specific group. Note the expression includes a phrase defining the number to a specific group:

• 
  

  Most of the students in my English class ask questions. (most - specific to those who are in my English class)

  
  


• 
  

  All of the students in my class want A's. (all - specific to those who are in my class)

  
  
  


• 
  

  Many of the students in my school want less homework. (many - specific to those who are in my school)

  
  


• 
  

  A few of the students who have low grades had to stay for a review session. (a few - specific to those who have low grades)

  
  


• 
  

  Few of the students who have low grades had to stay for a review session. (few - specific to those who have low grades)

  
  

So it means only your first example is correct. But it is correct if for example you write:

Most of the birds which are living in highlands can fly.

About The most I think it refers to the rules of the and there is nothing more.