Blog about English
When the relative pronoun can or cannot be omitted.
A relative pronoun can often be omitted when it functions as the object of a defining relative clause, but it normally cannot be omitted when it functions as the subject.
Compare The book that I bought with The book I bought, but not The book that is on the table with The book is on the table.
A relative pronoun functioning as the direct object can usually be omitted in a defining relative clause.
For example, The film that I watched and The film I watched are both standard.
A relative pronoun functioning as the subject of the relative clause cannot normally be omitted.
For example, The woman who lives here is a doctor. The form The woman lives here is a doctor does not preserve the relative-clause structure.
To determine whether a relative pronoun can be omitted, check whether another noun or pronoun already functions as the subject of the relative clause.
For example, The man who I met contains I as the subject, so who is the object and can be omitted.
Who can often be omitted when it functions as the object of a defining relative clause.
For example, The person who I called and The person I called are both standard.
Whom can be omitted when it functions as the object of a defining relative clause.
For example, The man whom I met and The man I met are both standard.
Which can be omitted when it functions as the object of a defining relative clause.
For example, The book which I bought and The book I bought are both standard.
That can be omitted when it functions as the object of a defining relative clause.
For example, The house that we bought and The house we bought are both standard.
That cannot normally be omitted when it functions as the subject of a defining relative clause.
For example, The car that caused the accident was damaged. Removing that would leave the relative clause without its subject.
Which cannot normally be omitted when it functions as the subject of a defining relative clause.
For example, The car which caused the accident was damaged.
Who cannot normally be omitted when it functions as the subject of a defining relative clause.
For example, The woman who lives next door is a doctor.
A relative pronoun cannot be omitted when a preposition directly precedes it.
For example, The person to whom I spoke is formal, but The person whom I spoke to can omit whom in less formal English.
When a preposition is placed at the end of a defining relative clause, the object relative pronoun can often be omitted.
For example, The person who I spoke to, The person whom I spoke to, and The person I spoke to are all possible.
Object relative pronouns can often be omitted after phrasal or prepositional verbs when the pronoun is functioning as the object.
For example, The person I was talking to and The problem we need to deal with.
Relative pronouns are not normally omitted in non-defining relative clauses, even when they function as objects.
For example, My brother, whom I visited yesterday, is a doctor. The form My brother, I visited yesterday, is not standard.
Object relative pronouns are most freely omitted in defining relative clauses.
For example, The book I bought yesterday was expensive.
Whose is not normally omitted because it functions as a possessive determiner within the relative clause.
For example, The woman whose car was stolen cannot normally be reduced by simply removing whose.
When and other relative forms referring to time can sometimes be omitted when the remaining clause is grammatically complete.
For example, The day when we met and The day we met are both standard.
Why can often be omitted after reason when the following clause remains grammatically complete.
For example, The reason why she left and The reason she left are both standard.
Omitting a relative pronoun is different from reducing a relative clause by using a participle or infinitive.
The book I bought is an omitted object relative pronoun, while The book bought yesterday is a reduced relative clause.
Object relative pronoun omission is especially common in speech and informal writing.
For example, The movie I watched yesterday is very natural in everyday English.
Object relative pronoun omission is also grammatically standard in formal English, although a full relative pronoun may sometimes be preferred for clarity.
For example, The report we received was incomplete is standard formal English.
An omitted relative pronoun should not make the sentence difficult to parse or create ambiguity.
A full relative pronoun can sometimes improve clarity when several possible grammatical analyses exist.
Object relative pronoun omission can occur even when the relative clause is long, provided the grammatical structure remains clear.
For example, The report we received from the company last week contained several errors.
Omit a relative pronoun only when it functions as an object in an appropriate defining construction.
Common mistakes include omitting a subject relative pronoun, omitting pronouns in non-defining clauses, omitting whose, and confusing pronoun omission with relative-clause reduction.