These questions ask you to choose or supply a relative form that fits both the noun before the clause and the job left open inside it. A quick antecedent, clause-type and role check is more reliable than choosing the word that merely sounds familiar.
Make three decisions
First identify the antecedent: is it a person, a thing or animal, or something that owns or has another noun? Next decide whether the clause identifies the antecedent or adds extra information. Finally, inspect the gap inside the clause: does the relative form act as subject, object, possessive determiner, or object of a fronted preposition?
| Signal | Choice and example |
|---|---|
| A person is the subject or object | Use who in ordinary wording: the pilot who noticed the fog. In a defining clause, that is also standard: the pilot that noticed the fog. |
| A thing or animal is the subject or object | Use which: the beacon which flashes at dusk. In a defining clause, that is equally grammatical: the beacon that flashes at dusk. |
| The next noun belongs to or is associated with the antecedent | Use whose for a person or a thing: a singer whose voice carries; a museum whose entrance moved. |
| The clause is non-defining | Use who, which or whose as appropriate, but not that: our guide, who knew the path, led us home. |
| A preposition is placed before a relative form referring to a person | Use whom in the formal pattern: the adviser with whom I spoke. The everyday stranded form the adviser who I spoke with is also standard. |
Do not turn a style preference into a grammar rule. In a defining clause about a thing, both which and that can be correct; in one about a person, both who and that can be correct. Let the wording and the available forms guide you only after the grammar check.
Where tempting choices go wrong
| Trap | How to reject it |
|---|---|
| Which is chosen because it can be a clause subject, even though the antecedent is a person | Subject role alone is not enough. Check the antecedent first and use a person form. |
| Who is chosen for a machine, structure or other nonhuman antecedent | Who can introduce a subject relative, but its normal antecedent is a person. Use a thing form instead. |
| Who, which or that is placed directly before a noun whose ownership must be shown | Those forms do not create a possessive link by themselves. The noun-before-noun pattern calls for whose. |
| Whose is avoided because the antecedent is not human | Whose is not limited to people. It can link an organisation, building or object to one of its parts or features. |
| Whom is selected merely because the sentence sounds formal | Whom is an object form, not a subject form. Confirm that a verb or preposition needs an object before using it. |
Try it
Which phrase uses a relative pronoun that matches its antecedent?
- the sensor which detected smoke
- the curator which opened the show
- the valve who controls the flow
- the mechanic which repaired the lift
Use the formal form required after the fronted preposition: The consultant to ___ the request was sent replied this morning.
- which
- whom
- who
- whose
Possessive-relative check: select all sentences that correctly use whose.
- The company which staff work remotely expanded.
- The cyclist whose helmet cracked was unhurt.
- The sculpture that surface gleams was cleaned.
- The theatre whose roof leaked closed early.