Prepositions in relative clauses: with whom, which... with

Start with the meaning

A preposition is a word such as to, with, from, in or about. It connects parts of a sentence. Choose it from the meaning of the verb or expression, not from the relative pronoun.

• You spoke to a nurse. / The nurse who you spoke to is here.
• We travelled with a neighbour. / The neighbour who we travelled with lives upstairs.

The relative clause gives information about the noun before it. The preposition still belongs to that clause: spoke to, travelled with. It may also belong to an adjective expression, such as be interested in.

The preposition at the end

You can put the preposition at the end of the relative clause. This works in defining clauses, which identify someone or something, and non-defining clauses, which add an extra fact with commas.

• The subject which I am interested in is history.
• Leo, who I used to work with, has retired.

The end position is less formal than putting the preposition before which or whom.

In a defining clause, you can use that or leave the relative pronoun out. Keep the preposition at the end. In a non-defining clause, keep who or which and do not use that.

• The charity that I work for needs volunteers.
• The charity I work for needs volunteers.

A formal pattern: preposition + whom or which

Put whom after the preposition for a person, and which for a thing. This is a formal pattern. Whom is an object form of who.

Do not put that immediately after the preposition. If you choose that, move the preposition to the end. Do not omit whom or which while leaving a preposition at the start.

Use the preposition once, not at both the start and end of the relative clause.

Whose + noun after a preposition

Whose shows possession or a relationship. It needs a noun after it. In formal written English, a preposition can come before whose + noun. You can put the preposition at the end instead.

The expression is stay with someone's family. Whose family replaces Kim's family. See Whose and whom in relative clauses.

Where and when

Where can introduce a clause about a place. When can introduce a clause about a time. They can express the meaning of a preposition + which.

Choose the preposition to fit the meaning: in a room, on a day. Do not add another in after where in this room example.

Compare the town where I work and the town which I visit. You work in a town, but you visit a town without in. Where does not replace every object which after a place noun.

You can leave out when after a time noun: the day the shop opened. With a place, an object-pronoun pattern can leave the preposition at the end: the room we met in. See Leaving out the relative pronoun: the people we met.

Quantity + of whom or of which

You can add information about part or all of a group with a number or quantity expression. Use of whom for people, and of which for things or animals. Put a comma before the added clause.

• There were five guides, two of whom spoke Italian.
• I tested three batteries, none of which worked.
• She lent me several novels, one of which I read on the train.

Other quantity expressions include all, most, many and a few. Keep of in this pattern.

What comes next

See Defining relative clauses: who, which, that and Non-defining relative clauses: extra information with commas for the two clause types. See Whose and whom in relative clauses for whose and formal whom, and Leaving out the relative pronoun: the people we met for clauses without a relative pronoun.