A relative pronoun can be the object of a preposition:
I found the keys which I was looking for.
That´s the woman who(m) I´m in love with.
- In informal English we usually put the preposition at the end of the relative clause and we omit the relative pronoun:
I found the keys I was looking for
That´s the woman I´m in love with.
- In formal English the preposition may come at the beginning of the relative clause, before the relative pronoun.
I found the keys for which I was looking.Note: We cannot put a preposition before that or who
That´s the woman with whom I´m in love.
More examples:
- listen to
The music is good. Julie listens to the music.
→ The music (which / that) Julie listens to is good.
→ The music (which / that) Julie listens to is good.
- work with
My brother met a woman. I used to work with the woman.
→ My brother met a woman (who / that) I used to work with.
→ My brother met a woman (who / that) I used to work with.
- go to
The country is very hot. He went to the country.
→ The country (which / that) he went to is very hot.
→ The country (which / that) he went to is very hot.
- come from
I visited the city. John comes from the city.
→ I visited the city (that / which) John comes from.
→ I visited the city (that / which) John comes from.
- apply for
The job is well paid. She applied for the job.
→ The job (which / that) she applied for is well paid
→ The job (which / that) she applied for is well paid