Learn the formal form “preposition + which/whom.” Rewriting it using relative adverbs is also important.
Basic Rules
This is a formal form in which a preposition remaining at the end of a sentence is moved before the relative pronoun:
“This is the house which he lives in.” (informal) → “This is the house in which he lives.” (formal)
“She is the person whom I spoke to.” → “She is the person to whom I spoke.”
Preposition + which can often be rewritten as a relative adverb:
“the house in which he lives” = “the house where he lives”
The company for which he works is very successful.
That is the reason for which she refused the offer.
The book whose cover is red / the book the cover of which is red. ← of which
Points to Note
① that cannot be used after a preposition: “× the house in that he lives” is incorrect.
② Choosing the preposition: Move the preposition used with the verb or adjective directly before the relative pronoun. “depend on → the person on whom we depend”
③ of which: Sometimes used instead of the possessive whose, especially for things.
- Preposition + which/whom: the formal form
- that cannot be used before a preposition (only which/whom)
- Preposition + which ⇔ relative adverb (in which = where, etc.)
- of which = whose (especially when the antecedent is a thing)
Practice
- Rewrite the following in the formal form (preposition + relative pronoun): This is the topic which we were talking about.
- Rewrite the following using a relative adverb: The city in which I grew up is now very different.
- Correct the error: The reason for that she was absent is unknown.