Defining vs non-defining
There are two types of relative clauses, defining and non-defining. In the grammar chart below, you can see the main differences between them.
Relative pronouns are the words that introduce relative clauses. They can act as the subject or the object of the relative clause.
Note that that can be used in informal English instead of who/whom/which but it is never used after commas, i.e. in non-defining relative clauses, or after prepositions.
- That’s the man who/that offered me the job.
- My mother’s older brother, who/
thatlives in New York, is coming to visit.
- That’s the house in which/
thatthey lived all their lives.
Which/that vs what
We use which/that as relative pronouns. They refer back to a noun or sentence.
- I gave her the letter which/that I had been keeping since the war. (which/that= the letter)
- He offered to help us, which was a nice gesture. (which= offering to help us)
We don’t use what as a relative pronoun. It cannot be used to refer back to a sentence or noun.
I gave her the letter what I had been keeping since the war. He offered to help us, what was a nice gesture.
We use what independently to mean ‘the thing/s that’.
- I didn’t like what he did.= I didn’t like the thing/s that he did.
- What I don’t understand is why we are here. (what= the thing that)
Prepositions in relative clauses
When the relative pronoun is the complement of a preposition, we can use the preposition before the relative pronoun or at the end of the relative clause.
Preposition + relative pronoun
It’s not very common to use prepositions before relative pronouns, we just do it in formal language.
- He wrecked the car for which he had paid a fortune.
- He was a man for whom everybody had great respect.
Note that after a preposition we can only use the pronouns whom or which. We cannot use
who or that after a preposition.
We can also use whose after a preposition.
- The team signed then the young Maradona, in whose skills everybody had their hopes.
Preposition at the end of the relative clause
The most common position of the preposition is at the end of the relative clause.
- He wrecked the car for which he had paid a fortune. (formal; not common)
- He wrecked the car (which/that) he had paid a fortune for. (more usual)
Relative adverbs introduce relative clauses, just like relative pronouns, but in this case, they are used to introduce information about time (when), place (where), or reason (why).
Note that we can use a preposition + which instead of a relative adverb, although this structure is more formal and not as common.
- The coach changed the time when the players had to get up.
- =The coach changed the time at which the players had to get up.
- The bench where they were sitting was dirty.
- =The bench on which they were sitting was dirty.
Quantifier + of which/whom
In non-defining relative clauses (=between commas), we can use of which/whom after a quantifier such as some, any, none, all, both, several, enough, many and few.
- Their daughters, both of whom are in university, don’t visit them very often.
- The students, none of whom had failed the exam, were thrilled.
- Their house was full of cats, most of which had been found in the street.
- The two rooms, neither of which had windows, were small and dirty.
We can also use a quantifier + of whose.
- I belong to a reading club, most of whose members are retired teachers.
- The parents, some of whose children were already grown-ups, marched down the street.