Pronun is a world that can be substituted for a noun, noun phrase or for other pronouns without changing the meaning of the sentence.

Like any pronoun, Relative pronouns are substituted for nouns and other pronouns that functions as subjects or objects in a sentence. Relative pronouns are mostly used when combining sentences in which a word or phrase is repeated.

Who / Whom

• Use who and whom when referring to beings with consciousness: people , animals (when presonifild) etc..


example:

The man who sold you that book is my teacher.


(Who is definite pronoun because the sentence mentions the person in advance)


• Use who when the pronoun is the subject of a verb.


example:

Arnold schwarzenegger is one of the most popular action movie actors.




Arnold schwarzenegger was the governor of California.




Arnold schwarzenegger, who is one of the most popular actors, was the governor of California.

• Use whom when the pronoun is the object of a verb, preposition, or infinitive.
example:

Betty is the president of Bedrock.




Wilma praised Betty at the meeting.




Betty, whom Wilma praised at the meetingm, is the president of Bedrock.

Whom replaces Betty, which is the object of the verb praised

Which / That

• Use that when referring to persons, or things in an essential relative clause.
example:


The book that is assigned to me is 400 pages.



• Use wich when referring to persons, or things in a nonessential relative clause.
example:

San Francisco, which is a great city in California, is where my brother lives.




Whoever / Womever

• Similar to who and whom except in an indefinite way.
example:

Someone sold you that book. He / she did not give you the right one.

Whoever sold you that book. He / she did not give you the right one.

(Whoever is the subject of the verb sold.)


You sold that book to someone. He / she is probably unhappy now.

Whomever you sold that book to, is probably unhappy now.

(Whomever is the object of the verb sold.)

Whose

• Use whose to indicates the possession
example:

Jack is the best in class. I borrowed jack's notebook.

Jack, whose notebook I borrowed, is the best in class.