ge11-5.2· Unit 5: Adjectives, Adverbs & Clauses· ~14 min

Relative clauses

Defining and non-defining relative clauses, relative pronouns, omission and prepositions.

Relative clauses give more information about a noun and begin with a relative pronoun: who/whom (people), which (things), that (people or things), whose (possession), and where/when/why (place, time, reason). A defining relative clause identifies which person or thing we mean and takes no commas (The man who phoned is my uncle). A non-defining relative clause adds extra, non-essential information and is separated by commas; it cannot use 'that' (My uncle, who lives in Baku, phoned). When the relative pronoun is the object of a defining clause, we can leave it out (the book (that) I read). In formal English a preposition can come before the pronoun: the house in which I grew up; the man to whom I spoke.

Key terms

Relative clause — A clause that gives more information about a noun and begins with a relative pronoun, such as who, which, that, whose, where or when.
Relative pronoun — A word (who, whom, which, that, whose) or relative adverb (where, when, why) that introduces a relative clause and links it to the noun it describes.
Defining relative clause — A relative clause that identifies which person or thing we mean. It is essential to the meaning and takes no commas, for example: The man who phoned is my uncle.
Non-defining relative clause — A relative clause that adds extra, non-essential information. It is set off by commas and cannot use 'that', for example: My uncle, who lives in Baku, phoned.
Omission of the pronoun — Leaving out the relative pronoun when it is the object of a defining clause, for example: the book (that) I read.
Preposition + pronoun — In formal English a preposition can come before the relative pronoun, using 'which' for things and 'whom' for people: the house in which I grew up; the man to whom I spoke.
Relative pronouns and adverbs
PronounRefers toExample
whopeopleThe woman who lives next door is a doctor.
whichthingsI bought a phone which has a good camera.
thatpeople or things (defining clauses only)This is the book that won the prize.
whosepossessionThat's the author whose books have sold millions.
whereplaceThis is the café where we first met.
whentimeI'll never forget the day when I started school.
Defining vs non-defining relative clauses
FeatureDefiningNon-defining
Commas?No commasAlways set off by commas
Essential information?Yes, identifies which noun is meantNo, adds extra detail only
Can use 'that'?YesNo, 'that' is never used
Can omit the pronoun?Yes, when it is the objectNo, the pronoun must stay
✎Joining two sentences with a relative clause
  1. 1Two sentences: I know a girl. She can speak five languages.
  2. 2Match the pronoun: The girl is a person and is the subject of 'can speak', so use 'who'.
  3. 3Join them: I know a girl who can speak five languages.
  4. 4Omit the object pronoun: When the pronoun is the object, it can be dropped: The film (that) we watched was boring.
✎Defining vs non-defining: the role of commas
  1. 1Defining (essential): The Old Town that attracts many tourists is in Baku. No commas, and the clause says which town we mean.
  2. 2Non-defining (extra): The Old Town, which attracts many tourists, is in the centre of Baku. Commas surround extra information.
  3. 3Why 'that' fails here: A non-defining clause cannot use 'that', so 'which' is required after the comma.
  4. 4Preposition in formal English: The conference to which they invited me was held in Geneva. The preposition comes before 'which'.
🚫Common mistake

A non-defining clause (the one in commas) cannot use 'that': write 'My grandfather, who is eighty-five, ...', never 'My grandfather, that ...'.

🚫Common mistake

Do not drop the pronoun in a non-defining clause. The pronoun must stay, and it can never be omitted when it is the subject of any clause.

⚠️Caution

Use no commas in a defining clause: 'The man who repaired my car was friendly.' Adding commas would turn it into a non-defining clause and change the meaning.

💡Note

You may omit the relative pronoun only when it is the object of a defining clause: 'the people I invited didn't come.' After a preposition, use 'which' or 'whom', never 'that': 'the colleague with whom I share an office.'

Rules

  1. 1Use who/that for people, which/that for things, and whose to show possession; that is common in defining clauses but is NEVER used in non-defining clauses.
  2. 2Non-defining relative clauses add extra information and are always set off by commas; defining relative clauses identify the noun and take no commas.
  3. 3You may omit the relative pronoun when it is the OBJECT of a defining clause (the film I saw), but not when it is the subject.
  4. 4After a preposition use 'which' for things and 'whom' for people (the topic about which we spoke; the woman with whom he works); 'that' cannot follow a preposition.
  5. 5Use 'where' for places, 'when' for times and 'why' for reasons; quantifiers combine with of which/of whom (many of which, most of whom).

Practice

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10 random questions per test

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