Clauses

Adjective Clauses

An adjective clause modifies a noun, just as an adjective does, but it has its own subject and verb. It usually starts with who, which or that, and sometimes with where or when. This first word links the clause to its noun and also does a job inside the clause.

What you’ll learn

Find the noun an adjective clause modifies
Tell an adjective clause from an adverb clause that starts with when or where
Work out the relative pronoun's job inside its own clause
Draw the dashed line joining the clause to its noun
Recognise a clause where the relative pronoun has been left out
Tell a restrictive clause from a non-restrictive one by its commas

Adjective clauses: a clause where an adjective would go

The old violin and the violin that she inherited do the same job: both tell you which violin. The second uses a whole clause, with its own subject (she) and verb (inherited). Notice the order: an adjective usually comes before its noun, but an adjective clause always comes after it.

Most adjective clauses are relative clauses. They begin with a relative pronoun: who, whom, whose, which or that. Sometimes the pronoun is left out (more on this below). A clause that begins with a relative adverb (where, when or why) is an adjective clause too.

The violin that she inherited needs new strings. — the clause tells you which violin.
We met the guide who found the trail. — it tells you which guide.
That is the year when the bridge closed. — the relative adverb when starts a clause that tells you which year.

The relative pronoun does two jobs

This is the part learners most often miss. In the violin that she inherited, the word that does more than connect the clause. It is also the direct object of inherited: she inherited that, meaning the violin.

So the pronoun goes inside the adjective clause, in the slot its job requires. A dashed line joins it to the noun it refers back to, its antecedent. The dashed line shows the connection; the slot shows the job. Not every that works like this: in a noun clause, that only connects (see two kinds of that).

Find the noun being described
violin. The clause comes right after it and tells you which violin.
Put the noun in place of the pronoun
that she inherited → She inherited the violin. The violin is what she inherited, so that is the direct object.
Place the pronoun in that slot, then draw the dashed line up to the noun
Write that in the direct-object slot of the lower clause, not at the front where it appears in the sentence.

“The violin that she inherited needs new strings.”

Reed-Kellogg — the pronoun sits in its own clause's object slot

det Determiner
nsubj Nominal subject
dobj Direct object
relcl Relative clause modifier
ROOT Root of the sentence
amod Adjectival modifier

Dependency — one relation per word, so only the internal job is named

Comparing the two views

Reed-Kellogg shows both jobs of that at once. It sits in the direct-object slot of the lower clause, and a dashed line joins it to violin. In the tree each word has only one head, so that is just the dobj of inherited. The link to violin goes through the verb of the clause instead: inherited is the relcl of violin.

The pronoun as subject, and its other jobs

The waiter who served us smiled. — here who is the subject of served, not its object: the waiter served us. It is the same construction with a different slot, so the dashed line now ends in the subject slot of the lower clause.

“The waiter who served us smiled.”

Reed-Kellogg — who sits in its own clause's subject slot

det Determiner
nsubj Nominal subject
relcl Relative clause modifier
dobj Direct object
ROOT Root of the sentence

Dependency — who is the nsubj of served; served is the relcl of waiter

Comparing the two views

Reed-Kellogg writes who in the subject slot of the lower clause and joins it to waiter with the dashed line. The tree gives who the relation of any subject, nsubj of served. Again the clause joins waiter through its verb: served is the relcl of waiter.

The relative pronoun comes at or near the front of its clause, whatever its job, so word order gives you no clue. Work out the job every time. It can be one of these:

Subject: the guide who found the trail (the guide found the trail).
Direct object: the violin that she inherited (she inherited the violin).
Object of a preposition: the friend with whom Nina studied, or, more often, the friend Nina studied with. The diagram puts the pronoun, or an x, on the line of the preposition.
Possessive: the neighbour whose dog barks. Like his or her, whose hangs on a slant under its noun, dog, and the dashed line runs to that slant.

Commas: restrictive and non-restrictive clauses

A restrictive clause tells you which one, and it has no commas. A non-restrictive clause only adds information about a noun the reader can already identify, and commas separate it from the rest of the sentence. Many course books call them defining and non-defining clauses.

The students who passed the test got a prize. — only some students passed, and only they got a prize.
The students, who passed the test, got a prize. — all the students passed, and all of them got a prize.

A non-restrictive clause never starts with that, and its pronoun cannot be left out: My brother, who lives in Cali, is a chef. The diagram, the tree and the Roles exercise treat both kinds of clause the same way, so look at the commas to tell them apart.

Common mistakes with relative pronouns

Spanish speakers often make these four errors with relative pronouns. Many of them come from Spanish que, which works for people and for things. Each item shows the error (✗) and a correct version (✓).

No extra pronoun. In the clause, that is already the object of bought. ✗ The phone that Omar bought it was cheap. ✓ The phone that Omar bought was cheap.
After a noun, use that, not what. ✗ The song what Marta wrote won a prize. ✓ The song that Marta wrote won a prize.
Use who for people and which for things (that for both). ✗ The nurse which helped us was kind. ✓ The nurse who helped us was kind.
No that after a preposition (Spanish en el que). ✗ This is the town in that she grew up. ✓ This is the town in which she grew up. ✓ This is the town that she grew up in.

Quick check

Which sentence has an adjective clause, and which noun does it modify? (a) I called Diego when the film ended. (b) We ate at the restaurant where Priya works.
Answer
(b). The clause where Priya works tells you which restaurant, so it is an adjective clause that modifies restaurant. In (a) the clause also comes right after a noun, Diego, but it says nothing about Diego. It tells you when I called, so it is an adverb clause, and it modifies the verb called.
In a Reed-Kellogg diagram, which slot of the lower clause does the relative pronoun go in? (a) The coach who chose Nina is strict. (b) The coach whom Nina chose is strict.
Answer
(a) who goes in the subject slot (who | chose | Nina), because the coach chose Nina. (b) whom goes in the direct-object slot (Nina | chose | whom), because Nina chose the coach. In both diagrams the dashed line joins coach to the pronoun. Both pronouns come first in their clause, so word order cannot show the job; putting the coach in their place can.
Where has a relative pronoun been left out in The bus we took was late? Could you also leave out that in The bus that leaves at six is full?
Answer
Between bus and we: the bus that we took. The clue is a noun followed directly by another subject and verb. The pronoun can be left out because it is an object (we took the bus), and the diagram writes an x in that slot. In the second sentence, that is the subject of leaves, so it must stay: ✗ The bus leaves at six is full.
Which sentence tells you that all the tickets were cheap? (a) The tickets that we bought online were cheap. (b) The tickets, which we bought online, were cheap.
Answer
(b). The commas make its clause non-restrictive: it only adds a fact about tickets the reader already knows, so all of them were cheap. The clause in (a) is restrictive. It tells you which tickets were cheap (the ones bought online), so others may not have been. Sentence (b) could not use that, because a non-restrictive clause never starts with that.

Key terms

Adjective clause: A dependent clause modifying a noun. Most are relative clauses; one introduced by where, when or why is an adjective clause too. Relation relcl for both. The violin that she inherited needs strings. That is the year when the bridge closed.
See: Modifier Relations
Relative clause: The main kind of adjective clause: one introduced by a relative pronoun — who, whom, whose, which, that — or by none at all. We met the guide who found the trail. The violin she inherited needs new strings. — the that is left out.
See: Modifier Relations
Relative adverb: where, when or why introducing an adjective clause, with an adverb’s job inside it. Drawn on a dashed slant from the noun down to the clause’s verb, which it modifies. That is the year when the bridge closed. We found the hotel where they stayed.
See: Adjectives & Adverbs
Relative pronoun: who, whom, whose, which, that — introduces the clause and, at the same time, fills a slot inside it. The violin that she inherited — that is the object of inherited. The guide who found the trail — who is its subject.
See: Nouns & Pronouns · Determiners & Function Words
Antecedent: The noun the relative pronoun refers back to — the one the clause modifies. The violin that she inherited — violin is the antecedent of that. The guide who found the trail — guide is the antecedent of who.
Restrictive clause: A clause that tells you which one is meant, written without commas; many course books call it a defining clause. A non-restrictive (non-defining) clause only adds detail, is separated from the sentence by commas and never starts with that. The violin that she inherited needs strings. — restrictive: it says which violin. My violin, which she inherited, needs strings. — non-restrictive: it adds detail about a violin already identified.

Practice on a real sentence

One adjective clause in a long sentence: who was little wiser (that is, not much wiser). It sits between commas, so it is non-restrictive. Find the noun it modifies and the job who does inside it. In Dependencies, the verb of the clause, was, is the relcl of that noun.

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