grammer correction

[14p...@skct.edu.in]

i want to know how can we correct grammer mistakes and if i give a sentence it should separate itself by subject,verb and object

example1:

when you come to coimbatore;

it should print as 

when will you come to coimbatore.

example2:

i write a letter yesterday;

it should  take this yesterday as past tense  and print as 

i wrote a letter yesterday.