There are often prepositions in relative clauses, and the relative pronoun is the object of the preposition. This means that the preposition can sometimes be omitted.
The preposition is normally placed at the end of the relative clause:
In formal or written English, the preposition is often placed before the relative pronoun, and in this case the pronoun cannot be omitted:
However, this is unusual in spoken English.
The information in these clauses is not essential. It tells us more about someone or something, but it does not help us to identify them or it.
Compare:
Punctuation
Non-defining relative clauses are always separated from the rest of the sentence by commas. The commas have a similar function to brackets:
Relative pronouns in non-defining clauses
Person | Thing | Place | |
Subject | who | which | |
Object | who/whom | which | where |
Possessive | whose |
This pattern is often used in spoken English, but in written or formal English you can also put the preposition before the pronoun: e.g. Stratford-on-Avon, about which many people have written is Shakespeare's birthplace.
Person | Thing | |
all of | + whom | + which |
any of | + whom | + which |
(a) few of | + whom | + which |
both of | + whom | + which |
each of | + whom | + which |
either of | + whom | + which |
half of | + whom | + which |
many of | + whom | + which |
most of | + whom | + which |
much of | + whom | + which |
none of | + whom | + which |
one of | + whom | + which |
two of etc... | + whom | + which |
See also Pronouns
Also see the page on Pronouns
It is important to see the difference between the two types of clause, as it affects:
As the name suggests, these clauses give essential information to define or identify the person or thing we are talking about. Obviously, this is only necessary if there is more than one person or thing involved.
In this sentence we understand that there are many dogs, but it is clear that we are only talking about the ones that like cats.
Punctuation
Relative pronouns
The following relative pronouns are used in defining relative clauses:
Person | Thing | Place | Time | Reason | |
Subject | who/that | which/that | |||
Object | who/whom/that/ | which/that/ | where | when | why |
Possessive | whose | whose |
Notes:
This noun usually appears earlier in the sentence:
The woman | who/that | spoke at the meeting | was very knowledgeable. |
Noun, subject of | relative pronoun referring to 'the woman', subject of 'spoke' | verb + rest of relative clause | verb + rest of main clause |
The woman | that | the man loved | was living in New York. |
Noun, subject of main clause | relative pronoun, referring to 'the woman', object of 'loved' | verb + rest of relative clause | verb + rest of main clause. |
(You can usually decide whether a relative pronoun is an object because it is normally followed by another subject + verb.)
4. Whose is used for things as well as for people.
5. Whom is very formal and is only used in written English. You can use who/that, or omit the pronoun completely :
6. That normally follows words like something, anything, everything, nothing, all, and superlatives.