1. The preposition does not disappear
When sentences are joined through a relative clause, the clause's verb often retains a preposition: work in, apply for, deal with or belong to. The noun before the clause supplies what the preposition refers to, but the preposition remains in one of the two positions.
The simplest check is to restore an ordinary clause. The landlord I complained to comes from I complained to the landlord. Since that meaning uses to in the ordinary clause, it also needs to in the relative clause.
A common error at this step is dropping the preposition. The result may look shorter or tidier, but loses the verb's required complement link and becomes ungrammatical for the intended meaning.
noun + (who/that/which/no relative pronoun) + subject + verb … + preposition ⟷ noun + preposition + whom/which + subject + verb …
- subject / S —
- The grammatical subject: who or what the clause is about; the verb agrees with it. In The book was written, the book is the subject, although someone else does the action.
- verb / V —
- A word for an action or state, such as work or be. The pattern determines its form.
- noun —
- A word naming a person, thing or idea: student, book, happiness.
- preposition —
- A word showing a relationship, such as in, on or from: from Ukraine.
- pronoun —
- A word used instead of naming a person or thing: I, you, she, it, they.
The landlord I complained to fixed the heating the same day.
The landlord I complained to fixed the heating the same day.
The ordinary clause is I complained to the landlord. To remains after the verb, at the end of the relative clause.
The folder in which we keep the invoices is on the top shelf.
The folder in which we keep the invoices is on the top shelf.
The same in from We keep the invoices in the folder is moved forward with which to the beginning of the relative clause.
The choir she sings in rehearses on Wednesdays.
The choir she sings in rehearses on Wednesdays.
In expresses the link to the choir: she sings in the choir. Sing can be used without a location, but would then not express that relationship to choir.
2. The everyday position: at the end of the clause
In everyday language, the preposition often stays after the verb: the person who I spoke to; the device which I work with. In a defining relative clause, an object relative pronoun can also be omitted. Who or which depends on what the preceding noun refers to.
The end of the clause is not always the end of the sentence. If the main predicate follows the relative clause, the preposition comes before it, rather than at the very end of the whole sentence.
This position is neutral. It is neither careless nor incorrect, and is the natural default in many situations. Moving the preposition forward is a deliberate stylistic choice.
The supplier we deal with never answers the phone.
The supplier we deal with never answers the phone.
There is no relative pronoun. With ends the relative clause, followed by the main predicate never answers.
The platform that the airport train leaves from is at the far end.
The platform that the airport train leaves from is at the far end.
The clause that the airport train leaves from ends with its preposition. Only then does is at the far end begin.
The speaker who I listened to yesterday spoke far too fast.
The speaker who I listened to yesterday spoke far too fast.
Who is normal when the preposition remains at the end. Whom is also possible here, but would sound conspicuously formal.
3. The formal position: before whom or which
In formal writing, such as a report, official letter, contract or covering note, a preposition can be moved to the start of the relative clause, immediately before the pronoun. This position has stricter requirements than the everyday pattern.
In this lesson's basic patterns, use preposition + whom for a person and preposition + which for a thing. These are not all possible constructions: in whose house is also correct, but whose with a noun has a different, possessive role.
Moving the preposition forward is not compulsory. The everyday version can also be correct in formal writing. Once you do move it, however, the remaining requirements of this pattern apply, and the pronoun choice is no longer free.
The address to which we sent the parcel turned out to be wrong.
The address to which we sent the parcel turned out to be wrong.
The address is a thing, so fronted to is followed by which. To which opens the relative clause.
The colleague with whom I share an office is on parental leave.
The colleague with whom I share an office is on parental leave.
The clause describes a person, so fronted with takes whom in this standard formal pattern.
The period during which the branch was closed is not counted.
The period during which the branch was closed is not counted.
During which is a natural formal way of specifying a period. Whether fronting suits a sentence depends on the preposition and construction, not the length of the word.
4. What a fronted preposition rules out
In the standard formal pattern, a fronted preposition requires an expressed whom or which: with whom, on which. Do not use relative that in this position or omit the relative pronoun.
Relative that cannot directly follow the fronted preposition: the desk on that I work is incorrect. This does not ban every sequence on that: in on that desk, that is a demonstrative determiner with a different role.
For a formal relative clause about a person, choose whom after the preposition. In the conversational pattern with the preposition at the end, who is usual: the person who I spoke to. This lesson targets that distinction between styles.
The device that the technician was complaining about is still broken.
The device that the technician was complaining about is still broken.
With relative that, the preposition must stay at the end. Fronted about that cannot introduce this relative clause.
The tenants about whom the manager was complaining have moved out.
The tenants about whom the manager was complaining have moved out.
The same content in the formal pattern requires whom, rather than that, because the preposition has moved forward.
The gallery we walked past was already closed.
The gallery we walked past was already closed.
The relative pronoun is omitted, so past can only stay at the end. It cannot be fronted without an accompanying relative pronoun.
5. The preposition depends on the construction and meaning
Some prepositions belong to established verb or adjective combinations: depend on, apply for, be responsible for. Others express the required location or direction: work in a room; work on a roof. Check both the word combination and the meaning you want to preserve.
Prepositions do not map mechanically between languages. English uses look at, wait for and explain to somebody, whereas marry someone has no preposition in this pattern. Learn the English combination rather than copying a source-language preposition.
First establish which preposition the English construction requires, then decide where to place it. Choosing a position cannot repair the wrong preposition.
The project she is responsible for has been postponed.
The project she is responsible for has been postponed.
Responsible for is an established combination. The noun project does not determine its preposition.
The candidate we were waiting for arrived an hour late.
The candidate we were waiting for arrived an hour late.
Wait takes for in this meaning. A source-language expression cannot justify substituting on.
The regulation on which the whole case depends was amended last year.
The regulation on which the whole case depends was amended last year.
Depend on retains its preposition even when on moves to the beginning with which.
6. An extra object after the preposition
Another common error is adding a second object after the preposition, such as it, him, them or her. Do not duplicate the relativised object in this standard English relative-clause pattern, even if a corresponding structure in another language would repeat it.
The noun before the clause already supplies that object role. Repeating the same role with a personal pronoun makes this pattern ungrammatical, even when the intended meaning is clear.
Remove a pronoun only when it duplicates the same role. An object with a different role remains: the number I called you from needs you as the person called.
The number I called you from belongs to the office.
The number I called you from belongs to the office.
Add nothing after from. Called you from it inside this relative clause would wrongly repeat the role of the number.
The neighbours we complained about apologised the next day.
The neighbours we complained about apologised the next day.
Neighbours already supplies the object of about. An added them would duplicate it.
The website I found the recipe on has disappeared.
The website I found the recipe on has disappeared.
On ends the relative clause. Do not add it afterwards to repeat the website, even if the equivalent wording would be natural in another language.
7. Choose one position, not both
A practical B1 guideline is to leave the preposition at the end in conversation and everyday correspondence. Choose the fronted version deliberately for a report, official letter, contract or presentation to a client.
The relevant preposition appears once in the relative clause. A conspicuous error in early formal writing is placing it both before the pronoun and at the end. That produces a faulty mixture of two alternatives.
When a clause describes a place or time, where or when can often be simpler than in which or on which. These are related tools, but here the target is specifically the preposition + relative pronoun pattern.
The agency I got the job through has closed down.
The agency I got the job through has closed down.
This is an everyday pattern. The pronoun is omitted, through ends the relative clause, and the main predicate follows.
The framework within which the audit was carried out is described in Annex 2.
The framework within which the audit was carried out is described in Annex 2.
In this formal written pattern, within which opens the relative clause and is followed by its subject and predicate.
The room in which the interviews took place was far too small.
The room in which the interviews took place was far too small.
Where could convey the same location, but in which was chosen deliberately to practise this pattern.
Common mistakes
Incorrect:The tutor to who I sent my essay replied at once.
Correct:The tutor to whom I sent my essay replied at once.
In the standard formal pattern with fronted to, use whom. For everyday who, leave to at the end: the tutor who I sent my essay to.
Incorrect:The desk on that I usually work is by the window.
Correct:The desk on which I usually work is by the window.
Relative that cannot follow fronted on. Use on which or that … on. In on that desk, that would instead be a demonstrative determiner in a different construction.
Incorrect:The parcel I was waiting for it arrived this morning.
Correct:The parcel I was waiting for arrived this morning.
Parcel already supplies the object of for. The added it duplicates that role; do not repeat it after the final preposition.
Incorrect:The choir she belongs has thirty members.
Correct:The choir she belongs to has thirty members.
Do not simply drop the preposition. Belong without to does not express the intended relationship, leaving the clause without the required complement link.
Incorrect:The consultant with whom we work with has raised her rates.
Correct:The consultant with whom we work has raised her rates.
Use the relevant preposition once: either before whom or at the end. Using both positions duplicates it rather than making the sentence more formal.
Incorrect:The company for she works is Norwegian.
Correct:The company for which she works is Norwegian.
A fronted preposition needs an expressed relative pronoun. The omission possible in the company she works for is not possible in this fronted position.