Relative clauses: defining and non-defining
Relative clauses add information about a noun: defining clauses identify which person or thing we mean (no commas), while non-defining clauses give extra, non-essential information (set off by commas).
Defining relative clauses
A defining relative clause tells us exactly which person or thing we are talking about, so we cannot remove it without losing essential meaning. We use 'who/that' for people, 'which/that' for things, 'whose' for possession, and 'where/when/why' for place, time and reason. We do not use commas, and we can leave out the relative pronoun when it is the object of the clause.
- •The woman who lives next door is a doctor.
- •This is the book that everyone is talking about.
- •The hotel where we stayed had a beautiful view.
- •The colleague (whom) I trust most has just resigned.
Non-defining relative clauses
A non-defining relative clause adds extra information that is not needed to identify the noun, so the sentence still makes sense without it. We always separate it with commas, and we never use 'that' or omit the pronoun. We use 'who' for people and 'which' for things, and 'which' can also refer to a whole previous clause.
- •My brother, who lives in Berlin, is visiting next week.
- •The new museum, which opened in May, is already very popular.
- •She failed the exam, which surprised everyone.
- •Our manager, whose office is on the top floor, rarely comes downstairs.
Prepositions and reduced clauses
In formal English the preposition can come before the relative pronoun, as in 'the city in which I grew up'. In everyday English we usually move the preposition to the end and often drop the pronoun: 'the city I grew up in'. We can also shorten relative clauses to participle phrases, using an -ing form for active meaning and an -ed/past participle for passive meaning.
- •The person to whom you spoke is the director. (formal)
- •The person you spoke to is the director. (informal)
- •The man sitting by the window ordered a coffee. (= who is sitting)
- •The documents signed yesterday are ready. (= which were signed)