who vs. whom (vs. which) again - can whom be used as a subject of the sentence

Question

Old English grammar books indicate a general rule of thumb for who vs whom -

• Who should be used to refer to the subject of a sentence.
• Whom should be used to refer to the object of a verb or preposition

Many people have raised similar questions in this forum and most have been answered, including this good example who vs whom. which one is appropriate.

However, I feel that my question could not be fully answered by either the conventional grammar book (not looking hard enough) or the posts in this forum. Hence this question below.

According to this link pronoun mistake #3, whom should be used. Can who be used in this example (seems strange)? If not, is whom used as a subject or an object?

The link above discussed the following example -

Huffington post had the following paragraph (date unknown) -

On New Year’s Eve at 11:45 am, Pope Francis called up the small community of the Carmelite nuns of Lucena in Cordoba, Spain, but they didn’t pick up the phone. Their once-large community has now dwindled to a mere five nuns, three of which are from Argentina, which is also the pope’s home country.

I interpreted the which here refers to the subject - the nuns, who are from Argentina. Is it correct that nuns are considered a "subject", not an "object"?

The author of the link (not of the Huffington post article) thought whom should be used, instead of which. Does this mean whom can be used as a subject of a sentence?

Answer 1

This is really several questions in one.

1. Of which v. of whom.

It is better to use "of whom" if the antecedent is human, but native speakers do sometimes use "of which" in informal contexts. This may be out of an unconscious desire to avoid the formal-sounding "whom".

• Det Insp John Mazzolai, of Greater Manchester Police, said: "This was a vicious assault on a man who was walking with five children, some of which were his." (BBC News)
• You leave it with a bunch of new friends, some of which you'll end up knowing for the rest of your life. (Blog in The Guardian)

2. Of who v. of whom.

Even though informally we can almost always replace "whom" with "who", we can't do this if "whom" is directly preceded by a preposition. Here, for most speakers (and certainly in standard English), only "whom" is acceptable English. So you always have to say "for whom", "of whom", "with whom", "to whom" - never "for who", "of who", "with who", "to who".

Of course, in most cases you can change the order of the words to move the preposition to the end. "Who" is then used informally: "Who did you give it to?" (a less formal way of saying "To whom did you give it?" v. formal.)

3. Is 'whom' the subject?

After prepositions, the object form of the pronoun is mandatory (with the exception noted above where the word order if changed). So, you always say "to me", "with me", "of me", never "to I", etc.

We would always say "three of them are from Argentina", never *"three of they".

In the phrase "three of whom are from Argentina", you are correct that "three of whom" is the subject of the clause. But "whom" is in the object form because pronouns always take the object form after prepositions.