What is Grammar Checker?

A grammar checker, in computing terms, is a program, or part of a program, that attempts to verify written text for grammatical correctness. - Wikipedia In school, you might have learned the basic rules of grammar. Most probably you have forgotten almost all the rules that you have learned in school. You might have various questions in your mind like: Is ending your sentences with a preposition a bad practice or there is any hard and fast rule that when you should use who or that or which? Where should you put a comma and apostrophe in a sentence?