B2 Grammar Clauses

Relative Adverbs: Where, When, Why

Relative adverbs introduce relative clauses that tell us about a place, a time or a reason — the town where I grew up, the day when we met, the reason why she left. They are a neat, natural alternative to preposition + which.

The three relative adverbs in English are where, when and why. Like relative pronouns (who, which, that), they introduce a relative clause that gives more information about a noun. The difference is that a relative adverb tells us about a place, a time or a reason, rather than standing in for a person or a thing.

Look at how each one attaches a clause to a noun: the place where I was born, the day when we met, the reason why she left. In each case the relative adverb links a noun to a clause that describes it, without needing a clumsy preposition out in front. This makes relative adverbs one of the most useful tools for building fluent, well-connected sentences in British English.

The Three Relative Adverbs at a Glance

Each relative adverb pairs naturally with a particular kind of noun — one of place, one of time, one of reason — and each has an equivalent built from preposition + which.

Relative adverb Noun type Preposition + which Example
where place (house, town, room, country) in/at/on which the house where I live = the house in which I live
when time (day, year, moment, time) on/in/at which the day when we met = the day on which we met
why reason (only the noun reason) for which the reason why she left = the reason for which she left

Where: Relative Adverb of Place

We use where after nouns of place to introduce a clause that describes that place. It replaces a phrase like in which, at which or on which.

Importantly, where can also follow more abstract nouns such as situation, case, point and stage, where the “place” is figurative:

When: Relative Adverb of Time

We use when after nouns of time — day, year, moment, time, period — to introduce a clause about that time. It replaces on which, in which or at which.

Why: Relative Adverb of Reason

We use why only after the noun reason, to introduce a clause explaining that reason. It is equivalent to for which.

The reason why / that / nothing: All three are correct — the reason why she left, the reason that she left, and simply the reason she left. In everyday British English we very often drop the relative word altogether: The reason I called is…

Omitting the Relative Adverb

In defining clauses, when and why can usually be dropped, especially in informal speech and writing:

However, where cannot normally be dropped — the place adverb has to stay:

Quick rule: You can usually drop when and why, but keep where. If you remove where, you must add the missing preposition at the end instead: the town where I grew up = the town I grew up in.

Relative Adverbs vs Relative Pronouns

It helps to see exactly how relative adverbs differ from the relative pronouns who, which and that. A relative pronoun replaces a noun (a person or thing) and acts as subject or object inside the clause. A relative adverb replaces a whole adverbial phrase of place, time or reason.

Word Type Replaces Example
where relative adverb in/at/on + which (place) the office where she works
when relative adverb on/in/at + which (time) the week when we moved
why relative adverb for + which (reason) the reason why it failed
who / that relative pronoun a person the woman who works there
which / that relative pronoun a thing the office which she rents

Notice the contrast: the office where she works (adverb — tells us about the place of working) versus the office which she rents (pronoun — the office is the object of rents). For more on the pronouns, see our guide to relative clauses.

Common Mistakes

Practice Exercises

Grammar Quiz

Choose the right relative adverb — where, when or why — for each sentence.

Matching Pairs

Match each noun to the relative adverb that introduces its clause.

Cloze Dropdown

Select where, when or why to complete each gap.

Flash Cards

Drill each relative adverb and its preposition + which equivalent.

Complete the Sentence

Type the correct relative adverb to finish each relative clause.

Unjumble

Reorder scrambled words into natural relative-adverb sentences.

Practise Relative Adverbs

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Explore related grammar topics:

All Grammar Topics Relative Clauses Adverbs Pronouns Determiners

Frequently Asked Questions

What is a relative adverb?
A relative adverb is a word — where, when or why — that introduces a relative clause giving more information about a noun of place, time or reason. For example, the town where I grew up, the day when we met and the reason why she left. Unlike relative pronouns, a relative adverb stands in for a whole adverbial idea of place, time or reason.
What are the three relative adverbs in English?
There are three: where for place (the house where I live), when for time (the year when I was born) and why for reason (the reason why he called). Each one attaches a clause to a particular kind of noun — a place noun, a time noun or the noun reason — and tells us more about it.
What is the difference between a relative adverb and a relative pronoun?
A relative pronoun (who, which, that) replaces a person or a thing and works as the subject or object inside the clause: the office which she rents. A relative adverb (where, when, why) replaces an adverbial phrase of place, time or reason: the office where she works. So which points to the office as a thing, while where points to it as a location.
How are relative adverbs related to preposition + which?
Each relative adverb is a shorter equivalent of a preposition followed by which. Where stands for in which, at which or on which; when stands for on which, in which or at which; and why stands for for which. So the house where I live equals the house in which I live, and the day when we met equals the day on which we met. The relative-adverb version is far more common in everyday English.
Can you leave out the relative adverb?
In defining clauses, when and why can usually be dropped: the day (when) we met, the reason (why) she left. This omission is very natural in spoken British English. However, where normally cannot be dropped — if you remove it, you have to add the missing preposition at the end instead, as in the town I grew up in.
Is it ‘the reason why’ or ‘the reason that’?
Both are correct, and so is using nothing at all. You can say the reason why she left, the reason that she left, or simply the reason she left. In everyday British English, dropping the relative word is extremely common: The reason I called is… Some writers prefer the reason that in formal contexts, but the reason why is fully standard.
Why is ‘the house which I live’ wrong?
Because live needs a preposition to connect to a place. You can say the house where I live (the relative adverb supplies the idea of in), or the house which I live in (the preposition is added at the end). But the house which I live leaves the preposition missing, so it is incorrect. Either keep where, or use which…in.
Can ‘where’ be used with abstract nouns?
Yes. Besides literal places, where often follows abstract nouns such as situation, case, point and stage, where the “place” is figurative: We’ve reached a point where we must decide, or There are cases where this rule does not apply. This is standard and very common in both speech and writing.
Why can’t I put a preposition before ‘when’ or ‘where’?
Relative adverbs already contain the meaning of the preposition, so adding another one is redundant. Avoid the day on when we met; say the day when we met or the day on which we met. Likewise, do not write the room where I sleep in it — the in it repeats what where already expresses. Just say the room where I sleep.
At what level should I learn relative adverbs?
Relative adverbs are usually introduced at B1 (intermediate) and refined through B2 and C1 on the CEFR scale, once learners are comfortable with basic relative clauses. They appear frequently in Cambridge B1 to C1 exams and in IELTS writing and speaking, where they help you connect ideas about place, time and reason smoothly and naturally.