Relative Clauses

What is a Relative Clause?

A relative clause adds information about a noun without starting a new sentence. Instead of writing two short sentences, you weave the second one in with a relative pronoun.

• Two short sentences: I know a woman. She speaks five languages.
• One sentence with a relative clause: I know a woman who speaks five languages.

The relative clause who speaks five languages tells us more about the woman. This is one of the key techniques that separate simple English from fluent English.

The Relative Pronouns

Defining vs Non-Defining — The Big Distinction

This is the single most important thing to understand about relative clauses.

Defining relative clauses

Give essential information — remove them and the sentence loses its meaning. No commas.

The student who scored the highest received a prize.

Remove who scored the highest and we don't know which student we mean.

Non-defining relative clauses

Give extra information — remove them and the sentence still makes sense. Commas around.

My brother, who lives in Paris, is a chef.

Remove who lives in Paris and we still know we're talking about my brother. The information is nice to have but not essential.

Rule: Non-defining clauses NEVER use that. Only who, which, whose, etc.

When Can You Drop the Relative Pronoun?

You can leave out who, which, or that when the pronoun is the object of the clause, in a defining clause only.

• With pronoun: The movie that we watched was excellent.
• Without pronoun: The movie we watched was excellent. ✓

You cannot drop the pronoun when it is the subject:

• ❌ The man lives next door is a doctor.
• ✅ The man who lives next door is a doctor.

Relative Clauses in Daily Life

Situation 1 — Introducing a Person

"Meet Priya, who I told you about last week."

Non-defining (Priya is already identified by name). Commas required.

Situation 2 — Talking About a Specific Object

"Have you found the keys that I lost yesterday?"

Defining — without the clause, we wouldn't know which keys. No commas. That is optional here (Have you found the keys I lost yesterday?).

Situation 3 — Adding a Whole-Sentence Comment

"The train was late, which made us miss the meeting."

The which here refers back to the whole situation, not a single noun. A useful pattern for connecting a comment to the previous idea.

Situation 4 — Recommending a Place

"There's a small place near the bridge where they roast the coffee themselves. It's the only café in town that opens before seven."

Where for the place, that for the defining detail that separates this café from every other one.

Situation 5 — Explaining Who Does What at Work

"Anjali, whose team handles refunds, is the person you want. The colleague sitting next to her covers billing, and anything flagged as urgent goes straight to the duty manager."

Whose for possession, then two reduced clauses — sitting and flagged — doing the same job with half the words.

Reduced Relative Clauses

Once you are comfortable with the full forms, English lets you cut them down. This is one of the clearest markers of an advanced writer.

Active → -ing

• The man who is sitting by the window → The man sitting by the window
• Passengers who are traveling to Delhi → Passengers traveling to Delhi

Passive → past participle

• The report that was written last year → The report written last year
• Items which were damaged in transit → Items damaged in transit

The reduction only works when the relative pronoun is the subject of its clause. The book that I read cannot become the book read — there, that is the object.

Quantifiers with Whom and Which

In non-defining clauses you can put a quantifier in front of the pronoun. This is formal, precise, and very useful in writing.

"The panel included six specialists, three of whom had worked on the original study."

"She made four recommendations, none of which were adopted."

"The building has two entrances, neither of which is marked."

Note that it is always of whom and of which — never of who and never of that.

Preposition Placement

When a preposition goes with the verb, you have two choices — one formal, one informal.

• Informal (English speakers use this daily): The woman who I spoke to was helpful.
• Formal: The woman to whom I spoke was helpful.

The informal version is fine in almost every context except strict academic or legal writing.

Sentences — Beginner to Advanced

Beginner

"I know a woman who speaks five languages."

A defining clause with who as the subject. The pronoun cannot be dropped.

Beginner

"The movie we watched last night was excellent."

A defining clause with the pronoun left out, because that would have been the object.

Intermediate

"My brother, who lives in Paris, is a chef."

Non-defining: commas on both sides, who not that, and the sentence still works without the clause.

Intermediate

"This is the hospital where my mother trained, and the year when she qualified is still on the plaque by the door."

Where for a place, when for a time — each replacing a heavier in which.

Advanced

"The committee approved the budget, which nobody had read in full, in under nine minutes."

Which referring to a noun, with the whole non-defining clause dropped into the middle of the sentence and the main clause resuming afterward.

Advanced

"She submitted three proposals, two of which were rejected outright, along with a fourth — written overnight and barely proofread — that the board accepted without discussion."

A quantifier clause (two of which), a reduced passive clause (written overnight), and a defining clause (that the board accepted) in a single sentence.

How Relative Clauses Elevate Your English

Basic: "I met a doctor. She works at the city hospital. She trained in Canada."

Elevated: "I met a doctor who works at the city hospital and who trained in Canada — a background that explained rather a lot about her bedside manner."

(Three sentences become one. Two defining clauses attach the facts to the doctor, and a third hangs off the noun that sums them up. Nothing has been added except structure.)

Basic: "The company published a report. Nobody in the industry believed the report. The report was later withdrawn."

Elevated: "The company published a report that nobody in the industry believed and that was quietly withdrawn six weeks later."

(Two defining clauses hang off the same noun, so the report is identified and judged in a single sentence. Notice how much of the original was carried by repeating "the report" — and how little is lost when the repetition goes.)

Memory Tips

The Deletion Test for Commas

Remove the clause and read what is left. If the sentence still identifies who or what you mean, the clause is extra — use commas. If the sentence now leaves the reader asking "which one?", it is essential — no commas. This single test decides every comma question in this lesson.

"That" Can Never Follow a Comma

Defining clauses take that or which; non-defining clauses take only which. So the moment you type a comma, that is off the table. My car, that is red, is old ✗ → My car, which is red, is old ✓.

Subject Pronouns Stay, Object Pronouns Can Go

If the relative pronoun is followed immediately by a verb, it is the subject and must stay: the man who lives next door. If it is followed by a new subject, it is the object and can be dropped: the movie (that) we watched.

Whose Is Not Only for People

Whose works perfectly well for things and organizations: a company whose shares had halved, a proposal whose wording nobody liked. The alternative, of which, is correct but heavy.

Whose vs Who's

Whose shows possession; who's is short for who is or who has. If you can expand it to "who is," write who's. Otherwise it is whose. Same test as its and it's.

Reduce Only When the Pronoun Is the Subject

The man who is sitting there → the man sitting there ✓, because who is the subject. The book that I read → the book read ✗, because that is the object. When in doubt, leave the clause in full — a long correct sentence beats a short broken one.

Common Mistakes vs Correct Forms

Formal vs Informal

Informal:

"That's the guy I was telling you about — the one whose brother runs the garage."

The pronoun dropped after guy, a dash instead of a comma, and whose used without ceremony. Completely natural in speech.

Informal:

"There's a place near the station that does breakfast all day, which is basically all I need from a restaurant."

That for the defining clause, then which commenting on the whole idea — the most common relative-clause pattern in spoken English.

Formal:

"The applicants, all of whom held recognized qualifications, were assessed against criteria to which they had been given access in advance."

All of whom and to which — the preposition placed before the pronoun rather than stranded at the end. This is the register of reports, contracts and academic writing.

Formal:

"The clause on which the objection rests was inserted in 2019 and has since been interpreted in two ways, neither of which the original drafters appear to have intended."

Idioms with Relative Clauses

"People who live in glass houses shouldn't throw stones" Meaning: Do not criticize others for a fault you share.

"He complained for ten minutes about colleagues who missed deadlines, which was brave for a man whose own report was three weeks late — people who live in glass houses shouldn't throw stones."

"All that glitters is not gold" Meaning: Something attractive on the surface is not always valuable underneath.

"The offer looked extraordinary until somebody read the clause that capped the payment at half the headline figure. All that glitters is not gold."

Both sayings are built on defining relative clauses — which is part of why they sound like settled wisdom rather than casual remarks.

Quick Reference

Practice

The exercises below start with combining short sentences into one and progress to deciding whether commas are needed, and when the pronoun can be dropped.