Relative Pronouns and Clauses – Adverbs

Relative clauses are used to join two sentences together into a more complex sentence and to give extra information about something. We use relative pronouns to introduce the relative clause, they can refer to the subject or object of a sentence.

For example:

The bicycle that I bought was stolen.
The man who owns the shop is from Canada.
My sister, who lives in London, is getting married next week.

In this section we will cover:

Defining and Non-defining Relative Clauses – definition, examples, features
Relative Pronouns (who, which, whose, that, whom) and
Relative Adverbs (when, where, why)
Prepositions and Relative Clauses
That/ Which vs what – perhaps the most common error.

1. Defining and Non-Defining Relative Clauses

The chart below outlines the main differences between defining and non-defining relative clauses with examples.

2. Relative Pronouns and Adverbs

Relative pronouns include:

Which – refers to an object.
Who – refers to a person
Whom – refers to a person (when the object/ often with a preposition)
Whose – refers to a person’s possession.
That – can be used for an object or person, replacing which/ that.

Relative Adverbs or ‘question words’ can replace relative pronouns (+ preposition) to make out speech less formal and sound more natural. They include:

Where – for a place
When – for a time
Why – for a reason.

See the examples below to see how adverbs can replace pronoun (+ preposition).

I can’t remember the name of the restaurant where we had our party.
I can’t remember the name of the restaurant that we had out party in.
I can’t remember the name of the restaurant in which we had our party.

July is the month when we are busiest.
July is the month that we are busiest in.
July is the month in which we are busiest.

My horrible boss was the reason why I left my job.
My horrible boss was the reason that I left my job
My horrible boss was the reason which I left my job.

3. Prepositions and Relative Clauses

We generally use the preposition + pronoun in very formal structures, we can also put the preposition at the end of the sentence, which is less formal.

The most common pronouns that follow a preposition like this are which and whom, though whose can also be used in this way. For example:

I did a course for which I paid a lot of money. (very formal)
I did a course which I paid a fortune for. (less formal)
I did a course that I paid a fortune for. (informal)

I’m not sure to whom I should send it to. (very formal)
I’m not sure whom I should send it to. (less formal)
I’m not sure who I should send it to. (informal)

He invited the people with whom he works. (very formal)
He invited the people whom he works with. (less formal)
He invited the people he works with. (informal)

4. Using what instead of that/ which

One of the most common mistakes people make with relative pronouns is using what when we should use that or which. For example:

I lost the book ~~what~~ that/ which you gave me.
The things ~~what~~ that/ which you said was very true.
A lot of children bring snacks ~~what~~ that/ which are unhealthy.

Note that in all the sentences above, that or which comes after a noun because it is a (defining) relative clause. We cannot use what as a relative pronoun.

We can use what when it is after a noun, this is often after subject + verb or it can be used at the start of a sentence. For example: