Relative clauses with relative adverbs

In addition to relative pronouns (that, which, who, whom, whose), relative clauses can also be introduced using the relative adverbs when, where, and why. Relative adverbs add information to a time, location or reason in the main clause, and like relative pronouns, they are placed directly after the time, location or reason that they describe. Unlike relative pronouns, however, relative adverbs cannot act as the subject of the verb in the relative clause.

This guide and a number of relative clauses with relative adverbs activities are available to download as PDF documents.

The graphic below provides a summary of how to use relative adverbs in relative clauses and some example sentences:

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Defining and non-defining relative clauses

Like relative clauses introduced by a relative pronoun, relative clauses introduced by a relative adverb can be defining or non-defining. Defining clauses add essential information, while non-defining clauses add nonessential information and are separated from the main clause with commas. It is not common for relative clauses beginning with why to be non-defining. Here are some examples:

• This is the book where he recorded all his memories. (defining)
• The library, where I spend most of my afternoons, is closing for renovations. (non-defining)
• Tomorrow will be the day when everything begins. (defining)
• I will never forget July 4th, when we had that amazing barbecue. (non-defining)

Where

Where is used to introduce a relative clause that describes a place or location:

• I’m looking for a house in a neighbourhood where there are lots of restaurants.
• We found a lovely spot on the beach where there weren’t many people.
• I know a place where the music is fine, and the lights are always low.

Where is used instead of the more formal adverbial phrase at/on/in which, which may be preferred in formal language:

• I’m looking for a house in a neighbourhood in which there are lots of restaurants.
• We found a lovely spot on the beach at which there weren’t many people.
• I know a place in which the music is fine, and the lights are always low.

Technically, if the relative clause is defining, it is possible to drop where. In this case, you would need to add the appropriate preposition in the end position, but this is uncommon and usually sounds quite strange, and is therefore probably best avoided:

• I’m looking for a house in a neighbourhood there are lots of restaurants in.
• We found a lovely spot on the beach there weren’t many people at.
• I know a place the music is fine, and the lights are always low in.

When

When is used to introduce a relative clause that describes a time:

• That was the moment when I realised I was in trouble.
• I’ll never forget the day when I met your mother.
• July will be the month when we launch the new product.

When is used instead of the more formal adverbial phrase at/on/in which, which may be preferred in formal language:

• That was the moment at which I realised I was in trouble.
• I’ll never forget the day on which I met your mother.
• July will be the month in which we launch the new product.

If the relative clause is defining, it is possible to drop when:

• That was the moment I realised I was in trouble.
• I’ll never forget the day I met your mother.
• July will be the month we launch the new product.

Why

Why is used to introduce a relative clause after the noun reason:

• That’s the reason why you should always take your phone with you.
• Did he give you a reason why he did that?
• There must be a reason why I have no luck in job interviews.

Why is used instead of the more formal adverbial phrase for which, which may be preferred in formal language (although this is not very common):

• That’s the reason for which you should always take your phone with you.
• Did he give you a reason for which he did that?
• There must be a reason for which I have no luck in job interviews.

If the relative clause is defining, it is very common to drop why from the sentence:

• That’s the reason (why) you should always take your phone with you.
• Did he give you a reason (why) he did that?
• There must be a reason (why) I have no luck in job interviews.

It’s also common to drop the noun ‘reason’ and use why to introduce a noun clause instead of a relative clause, provided the verb is able to take a noun clause as its object:

• That’s (the reason) why you should always take your phone with you.
• Did he give you why he did that? Did he tell you (a reason) why he did that?
• There must be why I have no luck in job interviews. I don’t know (a reason) why I have no luck in job interviews.

Common mistakes

Remember that a relative adverb cannot act as the subject of the verb in the relative clause. If the action in the relative clause is performed by the noun in the main clause, this would make the relative clause a subject relative clause and, in that case, only relative pronouns can be used:

• I like restaurants where serve fresh food. I like restaurants that serve fresh food.
• We visited a place where was very hot. We visited a place that was very hot.
• She talked about the day when changed her life. She talked about the day that changed her life.

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