Nominal Clauses in English

Overview

A nominal clause (also called a noun clause) is a clause that functions as a noun within a sentence. Just as a noun can be a subject, object, or complement, so can an entire clause. In the sentence What he said was true, the clause "what he said" acts as the subject. In I know what you mean, it acts as the object.

Nominal clauses are a C1 (Advanced) topic because they require you to think about sentence structure at a deeper level. They are extremely common in English -- both spoken and written -- and mastering them gives you the ability to express complex thoughts, report speech, and create nuanced arguments.

How It Works

Types of Nominal Clauses

That-Clauses

Introduced by "that" (which can often be omitted in informal English).

Function	Example
Subject	That he lied is concerning.
Object	I know (that) she is right.
Complement	The problem is that we have no budget.

When a that-clause is the subject, English often uses "the fact that" or moves it to the end with "it":

• The fact that he lied is concerning.
• It is concerning that he lied. (more natural)

Wh-Clauses

Introduced by wh-words: what, who, where, when, why, how, which, whose, whether.

Function	Example
Subject	What matters is your health.
Object	I don't know where he lives.
Complement	The question is whether we can afford it.
After preposition	It depends on what you want.

Important: In nominal clauses, use statement word order (subject before verb), not question word order.

• Wrong: I don't know where does he live.
• Right: I don't know where he lives.

Whether/If Clauses

For yes/no questions reported as clauses:

Direct question	Nominal clause
Will he come?	I don't know whether/if he'll come.
Is she ready?	I wonder whether/if she's ready.

Use "whether" (not "if") when:

• The clause is the subject: Whether he agrees is irrelevant.
• After a preposition: It depends on whether they accept.
• With "or not" directly following: Whether or not she comes...

Nominal Clauses as Different Sentence Parts

Role	Example	The clause
Subject	What you said hurt me.	what you said
Direct object	I believe that she is right.	that she is right
Subject complement	The truth is that nobody cares.	that nobody cares
Object of preposition	I'm worried about what he might do.	what he might do
Appositive	The idea that money buys happiness is false.	that money buys happiness

Examples in Context

English	Note
What matters is your health.	Wh-clause as subject
I don't know whether he'll come.	Whether-clause as object
The fact that he lied is concerning.	That-clause with "the fact" as subject
It depends on what you want.	Wh-clause after preposition
I believe that we can succeed.	That-clause as object
The question is how we should proceed.	Wh-clause as complement
Whoever finishes first gets a prize.	Whoever-clause as subject
Tell me what you think.	Wh-clause as direct object
The idea that the Earth is flat is absurd.	That-clause as appositive
I'm not sure why she left.	Wh-clause as object (after adjective)

Common Mistakes

Using question word order inside the clause

• Wrong: I don't know where does he live.
• Right: I don't know where he lives.
• Why: Inside a nominal clause, use normal statement order (subject + verb), not inverted question order.

Using "if" where "whether" is required

• Wrong: If he comes or not doesn't matter.
• Right: Whether he comes or not doesn't matter.
• Why: When the clause is the subject of the sentence, or when "or not" immediately follows, "whether" is required.

Omitting "that" when it causes ambiguity

• Wrong: I told her the plan was cancelled was a mistake.
• Right: I told her that the plan was cancelled was a mistake. or better: Telling her that the plan was cancelled was a mistake.
• Why: While "that" can often be dropped in object clauses, keeping it prevents confusion when the sentence structure is complex.

Confusing nominal clauses with relative clauses

• Wrong: (analyzing) Treating "what he said" as a relative clause
• Right: "What he said" is a nominal clause (= the thing that he said)
• Why: Nominal clauses act as nouns. Relative clauses modify nouns. What he said was true (nominal -- "what he said" = subject). The thing that he said was true (relative -- "that he said" modifies "thing").

Usage Notes

Nominal clauses are universal in English and show no significant difference between British and American usage. They are essential in:

• Academic writing: The evidence suggests that..., What this study demonstrates is...
• Everyday speech: I wonder if she's coming, Do you know what time it is?
• Business English: The concern is whether we can meet the deadline.

The ability to use nominal clauses fluently is one of the clearest markers of advanced English proficiency. Learners who rely only on simple sentence structures will find it difficult to express complex thoughts.

Practice Tips

• Clause spotting: Read a paragraph from a news article and underline every nominal clause. Label each one as subject, object, complement, or object of preposition. This builds structural awareness.

• Question transformation: Write ten direct questions, then convert each one into a nominal clause: Where does she live? becomes I don't know where she lives. Focus on getting the word order right.

• Complex sentence building: Start with a simple sentence like Health is important. Expand it by making the subject a nominal clause: What matters most is your health. Then expand the complement: What matters most is that you take care of your health.

Related Concepts

• Prerequisite: Relative Clauses: where, when, whose -- understanding how clauses work within sentences prepares you for nominal clauses
• Next steps: Explore cleft sentences and participle clauses for more advanced ways to structure complex ideas