Prepositions in relative clauses

The relative pronouns which and whom can function as the object of a preposition, as the examples set below:

However this use sounds rather formal, and it is much more common to place the preposition towards the end of the clause rather than before the relative pronoun, as in e.g.:

the room which we are staying inan achievement which I am very proud ofthe man who she has an affair withthe report which he is referring to

the room in which we are stayingan achievement of which I am very proudthe man with whom she has an affairthe report to which he is referring

and very often the relative pronoun is left out altogether, as in e.g.:

Note that if the verb in the relative clause is a phrasal verb which ends with a preposition, this preposition can never be placed in front of the relative pronouns which or whom, e.g.:

the room we are staying inan achievement I am very proud ofthe man she has an affair withthe report he is referring to

* This is just the key issue with which I have to put up. This is just the key issue which I have to put up with.* wrong.

If the relative pronoun is functioning as the indirect objectof the verb in the relative clause, the prepositions to or for are used, e.g.:

the girl (who/that)I lent my jacket tothe person (who/that) I poured a drink for