I met Anna + Kristoff is in love with her.

[BLenn]

There are various rules for the grammar of relative pronouns, so this part is the most confusing, I have a question for anyone, but when the antecedent is a person or a thing, you say that you use 'who' 'whose' 'who(m)' and then whom, but the objective relative pronoun whom can be omitted when studying grammar, so I thought it was correct, but I have no idea why it is wrong to use who in this parts of the example of Preposition + Relative pronoun, so I wondering if you could explain this part?

1. I met Anna + Kristoff is in love with her.
2. I met Anna who Kristoff is in love with.
3. I met Anna with whom Kristoff is in love.

 

[SoothingDave]

"Whom" is a word that people often don't know how to use properly, and its use is declining. Many never use it outside of fixed expressions.

"Whom" is a correct word to use in either sentence. "whom he is in love with" "with whom he is in love"

Many people will use "who" in the first example, because "whom" sounds stilted and formal.

Bottom line: You absolutely must use "whom" after the preposition. "With whom"

You can use either "who" or "whom" when the preposition is elsewhere, usually at the end. "Who" sounds a bit more natural because of the way usage is evolving.

 

[jutfrank]

I'm not entirely sure I understand the question. Are you asking why you need to use whom instead of who after a preposition? It's because it's the object of the verb, not the subject.

 

[Tarheel]

The word "who" is becoming more and more like "you", which can be used as either a subject or an object.