English lesson on pronouns who-whom

     There is often confusion about the use of who and whom.
     Who/whom are pronouns.
     Who is a subject pronoun, in the same way as 'he/she/they'.
     Whom is an object pronoun, in the same way as 'him/her/them'.

     In the sentence "John loves Mary",
     John is the subject of the verb 'love' and Mary is the object of his affection.

     Simple rule : If you can substitute he/they, use who.
                        If you can substitute him/them, use whom.

Subject	Verb	Object
Tom	saw	Julie.
Who	saw	Julie?
Julie	saw	whom?
→ Whom did Julie see?

1) Subject:

WHO
We use "who" when it is the subject of a verb i.e. when it refers to the person who takes an action.

◊ Julie played tennis. 'Julie' is the subject of the verb 'to play'.

◊ To find out the name of the player, we ask a question using 'who'
Who played tennis? Julie played tennis.

Subject	Verb	Object
Julie	played	tennis
Who	played	tennis?

' Who' is also used as the subject of a non-identifying relative clause:
◊ There's Mr. Jones, who bought the house next door.

2) Object :

WHOM
We can use 'whom' as the object of a verb, but it is very formal and not often used in spoken English.

◊ Formal English : Whom did you see?
◊ Everyday English : Who did you see?
'Whom' is used directly after a preposition.
◊ With whom did you play?

However, in conversational or informal English it is more usual to ask :
◊ Who did you play with?

Subject	Verb	Preposition	Object
Who	played	with	Julie?
Julie	played	with	whom?
→ With whom did Julie play?

'Whom' is also used as the object of a non-identifying relative clause:
◊ There's Mr. Brown, whom you met in London.

See also : who-whose-whom--that-which-where