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English Grammar Guide

Relative Clauses

B1 Relative Clauses

Section titled “ Relative Clauses”

English loves nesting. You start with a noun, then you attach a mini-sentence to describe it — like a backpack on a character in a video game. Relative clauses are those backpacks.

The woman who lives next door has a cat.

That gray bit? That’s a relative clause. It tells you which woman — not any woman, the one with the cat situation next door.

Before this, know:
Basic Sentence Structure (SVO)Nouns & PronounsB1 — Tense System

What relative clauses actually do

Section titled “What relative clauses actually do”

Every relative clause answers one question about the noun:

Which one? · What kind? · Where? · When?

English Mandarin equivalent Literal Mandarin
The man who called 打电话的男人 call-phone DE man
The book that I read 我读的书 I read DE book
The city where I grew up 我长大的城市 I grow-up-big DE city
The day when we met 我们见面的那天 we meet-face DE that-day

Notice the pattern? Mandarin stacks the description before the noun with 的 (de). English hangs it after with who / which / that / where / when.

Neither language is wrong. But if you translate word-for-word from Mandarin, you get:

❌ The I bought book is on the table.

And if you panic and split everything into two sentences:

“I bought a book. The book is on the table.”

…grammatically fine, but you sound like a GPS giving turn-by-turn directions instead of one smooth sentence.

The cast: who, which, that, where, when

Section titled “The cast: who, which, that, where, when”

Think of relative pronouns as job titles. Each one has a specialty.

Pronoun Refers to Example
who people the student who passed
which things/animals the phone which broke
that people OR things the guy that called / the car that crashed
where places the café where we met
when times the year when I graduated

WHO — for humans (mostly)

Section titled “WHO — for humans (mostly)”

The teacher who taught me retired last year.

Article Noun Verb Adjective Preposition

Who = the human filter. Teachers, neighbors, that one coworker who microwaves fish.

WHICH — for things (and sometimes pets with names)

Section titled “WHICH — for things (and sometimes pets with names)”

The laptop which I bought online arrived yesterday.

Article Noun Verb Adjective Preposition

Which is slightly more formal than that for things. In casual speech, most people say that anyway. Don’t stress — both work.

THAT — the Swiss Army knife

Section titled “THAT — the Swiss Army knife”

The person that called didn’t leave a message.

Article Noun Verb Adjective Preposition

That works for people and things in defining clauses. It’s the default in everyday English. If you’re unsure, that probably works.

WHERE and WHEN — place and time anchors

Section titled “WHERE and WHEN — place and time anchors”

The restaurant where we had dinner closed down.

Article Noun Verb Adjective Preposition

2020 was the year when everything changed.

Article Noun Verb Adjective Preposition

Where = in/at which place. When = at which time. You can sometimes replace them with that or which + preposition (the restaurant that we had dinner at), but where/when is cleaner.

Defining vs. non-defining: commas or no commas

Section titled “Defining vs. non-defining: commas or no commas”

This is the difference between identifying someone and adding a fun fact.

Same structure, different punctuation
Defining — NO commas (essential info)

The students who study hard pass the exam.

→ Not all students. Only the ones who study hard. The clause defines which students we mean. Remove it and the meaning breaks.

I need the keys that are on the counter.

→ Not any keys. Those keys. Specific keys. No commas.

Non-defining — WITH commas (extra info)

My brother, who lives in Shanghai, is visiting next week.

→ I have one brother (or you’re talking about a specific brother). The “lives in Shanghai” part is bonus info — nice to know, not essential for identifying him.

The Eiffel Tower, which is in Paris, is famous.

→ There’s only one Eiffel Tower. The Paris detail is trivia, not a filter.

Comma rules, plain and simple

Section titled “Comma rules, plain and simple”
Type Commas? Can you use “that”? Can you omit the pronoun?
Defining ❌ No ✅ Yes (who/which/that) ✅ Sometimes
Non-defining ✅ Yes ❌ No (that is banned) ❌ Never omit
My sister who is a doctor lives in Beijing.
My sister, who is a doctor, lives in Beijing.
If you have one sister (or one sister in context), 'who is a doctor' is extra info → non-defining → commas on both sides.
The people, that work here, are friendly.
The people who work here are friendly.
Defining clause = no commas. Also: that doesn't appear in non-defining clauses, and this one is defining anyway.

Anatomy of a relative clause (mermaid edition)

Section titled “Anatomy of a relative clause (mermaid edition)”

Here’s how the pieces lock together:

flowchart LR
    subgraph MAIN["Main clause"]
        S["Subject: The woman"]
        V["Verb: called"]
        O["Object: the police"]
    end


    subgraph RC["Relative clause (describes 'woman')"]
        RP["who"]
        V2["lives next door"]
    end


    S --> RC
    RC --> V


    style MAIN fill:#e8f4fd
    style RC fill:#fff3e0

Reading order: Start with the noun → read the relative clause as a parenthetical description → finish the main verb.

The woman [who lives next door] called the police.

Mandarin reading order is flipped:

**[住在我隔壁的]**女人报警了。 (Zhù zài wǒ gébì de nǚrén bàojǐng le.) [Live at my next-door DE] woman called-police.

Same story. Different sentence architecture. Your brain wants to front-load the description because that’s what 中文 trained it to do. English wants the noun first, then the backpack.

Omitting the relative pronoun (the stealth move)

Section titled “Omitting the relative pronoun (the stealth move)”

Sometimes the relative pronoun disappears — and the sentence still works.

With pronoun:

The book that I bought was expensive.

Without pronoun:

The book I bought was expensive.

Both correct. The omitted pronoun is the object of the relative clause — I bought [???] → I bought the book.

When you CAN omit

Section titled “When you CAN omit”
Pattern Example
Object of the clause The movie (that) we watched was boring
Object with preposition at end The city (that) he lives in is cold
Informal defining clauses The guy (who) I met yesterday

When you CANNOT omit

Section titled “When you CANNOT omit”
Pattern Example Why
Subject of the clause The man who called ← can’t drop Called needs a subject
Non-defining clauses My car**, which** is red ← can’t drop Commas = pronoun stays
After preposition (formal) The person to whom I spoke To whom stays together
The woman called me is my boss.
The woman who called me is my boss.
Called needs a subject → who can't be omitted. (The woman = subject of 'is', not of 'called'.)
The report I wrote it last week is done.
The report (that) I wrote last week is done.
You CAN omit that here (object position), but don't add it — that's double-marking the object.

Relative clauses in the wild: common patterns

Section titled “Relative clauses in the wild: common patterns”

Pattern 1: Describing people you know

Section titled “Pattern 1: Describing people you know”

The colleague who sits next to me speaks three languages.

Article Noun Verb Adjective Preposition

Mandarin: 坐在我旁边的同事会三种语言。 (Zuò zài wǒ pángbiān de tóngshì huì sān zhǒng yǔyán.) Sit at my beside DE colleague can three kinds language.

Pattern 2: Things you own or use

Section titled “Pattern 2: Things you own or use”

The app that I use every day crashed.

Article Noun Verb Adjective Preposition

Or omit: The app I use every day crashed.

Pattern 3: Places with memories

Section titled “Pattern 3: Places with memories”

The park where we first met is still there.

Article Noun Verb Adjective Preposition

Pattern 4: Non-defining bonus facts

Section titled “Pattern 4: Non-defining bonus facts”

Beijing, which is the capital of China, has great food.

Article Noun Verb Adjective Preposition

Commas hug the clause like parentheses. Remove the clause and you still know which Beijing — there’s only one.

Practice: fix these relative clause disasters

Section titled “Practice: fix these relative clause disasters”

Who / which / that

Section titled “Who / which / that”
The person which helped me was kind.
The person who helped me was kind.
People → who (or that). Which is for things.
The car who broke down is fixed.
The car that broke down is fixed.
Things → that or which. Cars aren't people (usually).

Where / when

Section titled “Where / when”
The day where we met was sunny.
The day when we met was sunny.
Times → when. Places → where.
The hotel when we stayed was cheap.
The hotel where we stayed was cheap.
Hotel = place → where. (Or: 'the hotel that we stayed at'.)

Commas

Section titled “Commas”
Students, who study hard, pass.
Students who study hard pass.
Defining — we're talking about a subset of students, not all students. No commas.
My phone which is an iPhone is old.
My phone, which is an iPhone, is old.
You have one phone in context → the iPhone detail is extra → non-defining → commas.

Relative clauses vs. two short sentences

Section titled “Relative clauses vs. two short sentences”

Both can be correct. Relative clauses are denser and more native-sounding in writing and formal speech.

Choppy (two sentences) Smooth (relative clause)
I met a woman. She works at Google. I met a woman who works at Google.
We visited a town. It was near the coast. We visited a town that was near the coast.
I remember the day. We got married then. I remember the day when we got married.

Mandarin actually prefers the relative-clause style too — 在谷歌工作的女人 — but because the description comes before the noun, English speakers learning Chinese get the opposite problem. You’re learning to delay the description until after the noun. Patience, then clause.

Relative Clause — cheat sheet

Defining (essential — no commas): noun + who / which / that / where / when + verb phrase

Non-defining (extra — commas both sides): noun, + who / which / where / when + verb phrase, + main verb

Omit pronoun when: noun + (that/who) + subject + verb ← pronoun is object

People: who / that · Things: which / that · Places: where · Times: when

Never in non-defining: that (use who/which instead)

Try this right now

Section titled “Try this right now”

Pick three nouns from your day: a person, a thing, a place. Write one defining relative clause for each — no commas. Then rewrite one as non-defining with commas.

Example:

  1. The barista who makes my coffee knows my order.
  2. The charger that I lost was expensive.
  3. The café where we had lunch, which closed last month, was my favorite.

Say them out loud. If you feel the urge to say “he” or “it” after the noun, swap in who/that/which. That’s the Mandarin topic-comment reflex leaving your system.

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