Whose & who & whom

Very briefly (as relative pronouns)

Who: (subject) The man who is standing on the corner is my uncle.

Whom: (object) The man to whom you gave the money is my uncle.

Whose: (possessive) The man whose coat is brown is my uncle.

(as interrogatives)

Who is singing the national anthem tonight?

Whom did they as

Hi,

Mr Philip's explanations were quite true but I believe " who" can be used both for (subject and object) as a relative pronoun and as a introgative.

1-I know the man Who is working on the ship.
2-I know the man who(m) you were talking on the ship.

1-

earlybird1-Who wrote this letter to you?
2-Who(m) did you write the letter to?

Yeah you're right I found who as an object or subject lots of time but the second example that you gave,I think it should be "who did you write the letter to ?"or "To whom did you write the letter?"

Earlybird is correct about the double usage of who. When I give an explanation, I always give the "traditional" differences, some of which, by usage, may be a little out of date.

PhilipEarlybird is correct about the double usage of who. When I give an explanation, I always give the "traditional" differences, some of which, by usage, may be a little out of date

I do know that "who" is used in both questions,but I wanted to explain that we use "who-----------to ?" or "to whom ---------------