when should we put comma

we have to give comma to give a small pause . eg : i want a mango , apple , bannana and orange .  

To give small pause we use comma.

Note:small pause means small pause than full stop.full stop is used when u have to end a sentence.i might be knowing it :)

In general, the comma is used where ambiguity might otherwise arise, to indicate an interpretation of the text such that the words immediately before and after the comma are less closely or exclusively linked in the associated grammatical structure than they might be otherwise. The comma may be used to perform a number of functions in English writing. It is used in generally similar ways in other languages, particularly European ones, although the rules on comma usage – and their rigidity – vary from language to language.

comma is placed in a sentence  2 give a small pause in between 

eg- karan like fooball,tennis n atheletics. 

WHEN WE WNT TO GIVE A PAUSE TO THE SENTENCE

When we want the reader to give a pause .

it is use to separate 3 or more items of series