Preposition + relative pronoun
Definition
In formal relative clauses, a preposition can appear before whom for people or which for things. This is called a preposition-fronted relative clause: the person to whom I spoke, the issue about which we argued.
Examples
-
The person to whom I spoke was helpful.
Whom refers to a person and follows the fronted preposition to.
-
The proposal about which they argued was withdrawn.
Which refers to a thing and follows about.
-
The period during which sales fell was brief.
The fronted preposition expresses a time relationship.
Formal fronting vs. informal preposition stranding
The colleague to whom I wrote replied immediately.
The preposition appears before whom.
The colleague who I wrote to replied immediately.
The preposition remains at the end of the relative clause.
Both patterns can be grammatical. Fronting is more formal, while stranding is common in speech and ordinary writing.
That cannot follow a fronted preposition
Use whom or which after a fronted preposition. In an informal stranded pattern, who, which, that or no relative pronoun may be possible depending on the clause.
-
The company for which she works is expanding.
Which follows the fronted preposition for.
-
The company that she works for is expanding.
That is possible because the preposition is stranded at the end.
Common mistakes
The person to that I spoke was helpful.
The person to whom I spoke was helpful.
That cannot follow a fronted preposition; use whom for a person.
The topic about whom we spoke was sensitive.
The topic about which we spoke was sensitive.
Use which for a thing or topic, not whom.
Quick check
Question 1 of 3
Which formal relative clause refers to a person?
Use to whom when the antecedent is a person and the preposition is fronted.Which formal relative clause refers to a thing?
Use by which for a thing when the preposition is fronted.Which informal version correctly strands the preposition?
In the informal pattern, who introduces the clause and to remains at the end.Nice work — you've completed the quick check.
It's free. No ads. No credit card.