Grammar Guides / English / Relative Clauses: Who, Which, That

🔗 Relative Clauses: Who, Which, That

Add extra information to sentences using relative pronouns

B1 10 min read 5 sections

Defining Relative Clauses

Defining relative clauses give essential information — without them, the sentence doesn't make sense or the meaning changes. They use "who" (people), "which" (things), or "that" (both). No commas.

Relative Pronoun	Used For	Example
who	People	The woman who lives next door is a doctor.
which	Things/animals	The book which I bought is very good.
that	People or things	The man that called you is my boss.
that	People or things	The car that I want is too expensive.
where	Places	The restaurant where we ate was excellent.
when	Times	I remember the day when we first met.
whose	Possession	The student whose essay won is here.

Tip: "That" can replace "who" and "which" in defining clauses: "The man who/that called" and "The book which/that I bought" are both correct. In casual English, "that" is actually more common than "which" for things.

Non-Defining Relative Clauses

Non-defining relative clauses add extra information that is NOT essential — you could remove it and the sentence would still make sense. They are always enclosed in commas and CANNOT use "that."

Non-Defining (extra info, commas)	Defining (essential info, no commas)
My sister, who lives in Berlin, is visiting.	The sister who lives in Berlin is visiting. (I have more than one)
Paris, which is the capital of France, is beautiful.	The city which is the capital of France is beautiful.
Mr. Smith, who is 60, is retiring.	The man who is 60 is retiring. (Which 60-year-old?)
My car, which I bought last year, broke down.	The car which I bought last year broke down.

Tip: CRITICAL: You CANNOT use "that" in non-defining clauses. "My sister, that lives in Berlin" is WRONG — it must be "My sister, who lives in Berlin." Also, you cannot omit the relative pronoun in non-defining clauses.

Relative Pronouns as Objects — Omission

When the relative pronoun is the OBJECT of the clause (not the subject), you can often omit it entirely in defining clauses. This is very common in spoken English:

Full Form	Omitted (common in speech)	Why Omission Works
The book which I read was good.	The book I read was good.	"I" is the subject, "which" is the object → can omit
The man who I met was nice.	The man I met was nice.	"I" is the subject, "who" is the object → can omit
The film that she recommended.	The film she recommended.	"She" is the subject → can omit "that"

Tip: You can ONLY omit the relative pronoun when it's the object. You can NEVER omit it when it's the subject: "The man who called me" — you cannot say "The man called me" (that changes the meaning entirely).

Where, When, Whose

Three special relative words for places, times, and possession:

Word	Replaces	Example	Alternative
where	in/at which (place)	The city where I was born is small.	The city in which I was born...
when	in/at/on which (time)	I remember the day when we first met.	I remember the day on which...
whose	of whom / of which (possession)	The woman whose car was stolen reported it.	The woman, the car of whom... (very formal)

Tip: "Whose" works for both people AND things: "The house whose roof was damaged" is correct, though "The house the roof of which..." is more formal. "Whose" is always followed by a noun.

Common Mistakes with Relative Clauses

German and English relative clause systems differ in several important ways:

Mistake	Correct	German Influence
"The man which called me"	"The man who called me"	German "der" works for both people and things; English distinguishes who/which
"The book, that I bought"	"The book that I bought" (no comma) or "The book, which I bought"	"That" cannot be used in non-defining clauses
"The woman, who she is my neighbor"	"The woman, who is my neighbor"	Don't add an extra subject pronoun after the relative pronoun
"The city what I visited"	"The city that I visited"	"What" is NOT a relative pronoun in English
"The house in that I live"	"The house in which I live" or "The house that I live in"	After a preposition, use "which" not "that"

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🔗 Relative Clauses: Who, Which, That

Defining Relative Clauses

Non-Defining Relative Clauses

Relative Pronouns as Objects — Omission

Where, When, Whose

Common Mistakes with Relative Clauses

Practice with Interactive Quizzes

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