Reduced relative clauses

A relative clause can often be trimmed down without changing its core meaning, though tense or modal meaning can become implicit, and occasionally the reduced form means something slightly different. Doing this constantly is a big part of what makes fluent writing and speech sound smooth instead of clunky. You already know two of three common tools for this; this article recaps them briefly and adds a genuinely new one: turning a relative clause into a to-infinitive.

Quick shortcut. In a defining clause, the pronoun can often be dropped when it's the object of its clause (the film I recommended). It can often become an -ing or -ed participle when it's the subject of its clause (the man standing by the door, the bridge built in 1990). And after a superlative, a sequence word (first, next, last), only, or a general/indefinite word like something, it can often reduce all the way to a to-infinitive (the first person to arrive, nothing to worry about).

Two techniques you already know

In a defining clause, when the relative pronoun functions as the object of the verb or a preposition in its clause, you can often simply drop it. This is covered in full in Basic relative clauses — it doesn't work in a non-defining clause with commas, where the pronoun always stays (My car, which I bought last year, is red — never My car, I bought last year, is red), and it doesn't work when the preposition comes right before whom/which in a formal style: the person to whom I spoke keeps its pronoun, but the pronoun can drop once the preposition moves to the end instead — the person I spoke to:

• the film that I recommended → the film I recommended
• the keys that you were looking for → the keys you were looking for

When the pronoun is the subject of its clause, you can often turn the clause into a participle — -ing for active meanings (especially ongoing, general, or simultaneous actions), and a past participle for passive meanings (including completed passive events), often ending in -ed but sometimes irregular (built, written, made). This is covered in full in Participle clauses:

• the man who is standing by the door → the man standing by the door
• the bridge that was built in 1990 → the bridge built in 1990

This article assumes you're comfortable with both of those. What's new here is a third way to reduce a relative clause — one that works differently from the other two.

The new tool: reducing to a to-infinitive

Some relative clauses reduce all the way down to a to-infinitive (to + base form), with the relative pronoun disappearing, and often the subject and a modal of possibility, suitability, or necessity (can, should, need to) becoming implicit in the meaning of to as well. Unlike the participle pattern above, this works whether the original pronoun was the subject or the object of its clause — what matters here isn't grammatical role, but the kind of meaning the clause expresses: an achievement, an order of events, a task, or a possibility/suitability/necessity. The patterns below — superlatives, sequence words, only, and indefinite words — are the most common B2 triggers for this, though the same to-infinitive pattern can also follow other, definite nouns naming a task or expected event (the person to contact, the next train to arrive), covered in the second section. Not every relative clause after these trigger words reduces this way, though — it depends on whether that meaning is really there. A clause about someone's general ability, for instance, usually doesn't reduce this way: the man who can speak French normally stays as a full clause, or becomes the man able to speak French, not the man to speak French — ability isn't the same as an achievement, a task, or a possibility/necessity.

After a superlative, a sequence word, or only

When a relative clause follows a superlative (the best, the smartest), a sequence word (the first, the second, the next, the last), or only, and the clause describes an achievement or an order of events, it often reduces to a to-infinitive:

• She was the first person who arrived at the party. → She was the first person to arrive at the party.
• He was the last one who left the building. → He was the last one to leave the building.
• Maria was the only student who passed the exam. → Maria was the only student to pass the exam.

With evaluative words and superlatives, the same pattern can also express suitability or a recommendation, rather than an achievement: the best book to read, the easiest way to solve the problem, the safest place to stay.

This doesn't apply to every relative clause in this position, only ones expressing that kind of meaning: the best film that I saw this year stays as it is, or drops its object pronoun (the best film I saw this year) — it doesn't become the best film to see this year, which would mean something different (a recommendation, not a memory).

After an indefinite word, or a noun naming a task or requirement

Indefinite pronouns such as something, nothing, and anyone, place adverbs such as nowhere, and indefinite noun phrases like a lot of work or a good place combine naturally with a to-infinitive when the relative clause expresses possibility or necessity, often carrying a modal like can or should:

• I need something that I can wear to the interview. → I need something to wear to the interview.
• There's nothing that we can do about it now. → There's nothing to do about it now.
• She has no one that she can talk to. → She has no one to talk to.
• We have a lot of work that we need to do before Friday. → We have a lot of work to do before Friday.

The same pattern also reduces relative clauses after definite, already-identified nouns, as long as the clause names a task, purpose, or expected event rather than an ordinary fact: the person that I need to contact → the person to contact; the next train that arrives → the next train to arrive.

If the relative pronoun was the object of a preposition, that preposition simply stays at the end, right where it was: no one to talk to, nothing to worry about, a chair to sit on. This reduction works well when the modal expresses possibility or necessity; a modal like might (uncertainty) doesn't reduce the same way — the only person who might know can't be shortened without changing the meaning. The only person to know is grammatical, but it means "the only person who knows/knew," not "who might know."

A passive version: to be + past participle

For a passive meaning, the form is to be + past participle instead of a plain infinitive:

• the first woman who was elected president → the first woman to be elected president
• a lot of work that needs to be done → a lot of work to be done

The active and passive versions mean different things: the first person to choose means that person does the choosing; the first person to be chosen means someone else chooses that person.

Adding for + noun/pronoun

When the doer of the infinitive is different from — or not obvious from — the main sentence, for + noun or pronoun can go directly before the infinitive (the object form is used: for him, for them, not for he, for they):

• This isn't the right time for us to discuss it.
• Here's a good book for beginners to read.

When the doer is already clear from the main clause, for isn't needed: I need something to wear, not usually I need something for me to wear.

Common mistakes

• ❌ The book reading was fascinating. → ✅ The book I read was fascinating. (book reading would be understood as a compound noun — a reading event — not as a participle describing the book; an object clause like this one drops the pronoun instead of becoming a participle)
• ❌ She was the first person arrived. → ✅ She was the first person to arrive. (the infinitive needs its to — it doesn't just disappear along with the pronoun)
• ⚠️ I need something to write. means "I need a topic or text to write" — for "I need a pen," the meaning is ✅ I need something to write with. (a preposition the original clause needed — something that I can write with — has to stay in the reduced version too)
• ❌ He's the only one to can help. → ✅ He's the only one who can help / the only one able to help. (can and to aren't combined; for a completed action, He was the only one to help me means "he was the only one who helped me")
• ❌ The man to speak French got the job. → ✅ The man who can speak French got the job. (infinitive reduction expresses achievement, task, order, or possibility/necessity — not an ordinary clause describing someone's ability)

Quick check

Reduce each relative clause using the most natural technique.

1. This is the photo that I took last year.
2. The man who is waiting outside is my brother.
3. She was the first person that arrived at the party.
4. There's nothing that we can do about it.
5. The letters that were sent yesterday haven't arrived yet.

Key takeaways

• In a defining clause, the relative pronoun can often be dropped when it's the object of its clause: the film I recommended. It always stays in a non-defining clause with commas.
• A subject clause can often become an -ing or past participle: -ing for active meanings, a past participle (often -ed, sometimes irregular) for passive meanings, including completed passive events: the man standing by the door, the bridge built in 1990.
• After a superlative, a sequence word (first, next, last), only, or an indefinite word like something or nowhere, a clause expressing achievement, order, possibility, or necessity often reduces to a to-infinitive: the first person to arrive, nothing to worry about. The same pattern also follows definite nouns naming a task or expected event: the person to contact.
• Unlike the participle pattern, the infinitive pattern works for both subject and object clauses, and any preposition the original clause needed stays at the end: no one to talk to. For a passive meaning, use to be + past participle: the first woman to be elected president.
• When the doer of the infinitive isn't obvious, for + noun/pronoun can be added before it: a good book for beginners to read.