Nominal Clauses in English

In Brief

A nominal clause is a clause that fills a position often filled by a noun phrase: What matters is your health; I know what you mean; the problem is that we are late. Common types begin with that, a wh-word, or whether/if. In embedded questions, use statement word order—not direct-question order: I wonder where she is, not I wonder where is she.

Overview

A clause is a group of words built around a verb. A nominal clause—also called a noun clause—lets an entire situation, fact, question, or possibility act like a noun phrase. For example, the answer can be the object (the person or thing affected by the verb) in I know the answer. The longer unit what you mean fills the same object position in I know what you mean.

Nominal clauses can also be subjects (what the sentence is about), subject complements (information identifying or describing the subject), and complements of adjectives, nouns, and prepositions. They are essential in conversation, reporting, argument, and academic writing because they package complete ideas inside larger sentences.

At C1, the challenge is not simply recognising these clauses. You need to choose accurately among that, whether, if, and wh-forms; maintain embedded-clause word order; control formal patterns such as extraposition; and distinguish embedded questions from free relative clauses.

How It Works

The main clause types

Type	Typical marker	Example	Meaning packaged by the clause
Declarative content clause	that (sometimes omitted)	I believe (that) the plan will work.	a statement or claim
Embedded wh-question	who, what, where, when, why, how	We asked why the plan had failed.	an open question
Embedded alternative question	whether or sometimes if	I wonder whether/if it will work.	a yes/no choice
Free relative clause	what, whoever, whichever, where	Take what you need.	a person, thing, or place identified by the clause
Non-finite nominal clause	infinitive or -ing form	To leave now would be rude.	an action or situation without a fully marked tense

A finite clause has a verb marked for tense or agreement, as in she is ready or they arrived. A non-finite clause uses an infinitive or an -ing form, as in to leave or leaving early. The central focus here is finite that-, wh-, and whether-clauses, but non-finite clauses belong to the wider family.

The jobs nominal clauses perform

Function	Pattern	Example
Subject	Clause + verb	What matters is your health.
Direct object	Verb + clause	I understand what you mean.
Subject complement	Subject + be + clause	The problem is that nobody checked.
Adjective complement	Adjective + clause	I am pleased that you came.
Noun complement	Noun + clause	The fact that he lied is concerning.
Preposition complement	Preposition + wh-clause	It depends on what you want.

A complement is a word or group of words needed to complete the meaning of another expression. In the fact that he lied, the that-clause specifies the content of fact. This is different from a relative clause: in the claim that shocked us, that represents the subject of shocked and the relative clause describes claim. In the claim that the figures were wrong, that does not fill a role inside the clause; the clause states what the claim was.

That-clauses

A that-clause presents information as a statement, belief, report, reaction, or fact:

• She admitted that she had forgotten.
• We are confident that the figures are accurate.
• The possibility that prices may rise worries investors.

After many common reporting and thinking verbs, that can be omitted: I think (that) you are right. It is more often retained when the clause is long, formal, separated from its controlling word, or potentially hard to parse. At the beginning of a sentence, it cannot normally be omitted: That the data were incomplete was obvious.

A subject that-clause is grammatical but often sounds formal or heavy. English commonly moves it to the end and uses anticipatory it as a placeholder subject:

• Formal/heavy: That the deadline was missed is unfortunate.
• More usual: It is unfortunate that the deadline was missed.

This movement is called extraposition (placing a heavy clause later in the sentence).

Embedded wh-questions

An embedded question is a question placed inside a larger statement or question. It uses a wh-word but follows statement word order:

• Direct question: Where is she?
• Embedded question: Do you know where she is?

Do not add question-style do/does/did inside the embedded clause:

• Direct: Why did they cancel it?
• Embedded: I wonder why they cancelled it.

The whole sentence takes a question mark only if the main clause is a question. I wonder where she is. is a statement; Do you know where she is? is a question.

When the wh-word itself is the subject, there is no visible change in order: Who called? → I asked who called.

Whether and if

Use whether or if for an embedded yes/no question:

• I don't know whether he'll come.
• I don't know if he'll come.

The two are often interchangeable after verbs such as ask, know, and wonder, especially in conversation. Whether is required or strongly preferred in several patterns:

• before an infinitive: We must decide whether to continue.
• directly after a preposition: It depends on whether they agree.
• with or not immediately following: Tell me whether or not you agree.
• as a subject clause: Whether it succeeds depends on funding.
• when presenting explicit alternatives: We discussed whether to stay or leave.

Compare if meaning “whether” with conditional if: I don't know if she is home asks about her location; I'll call if she is home states a condition.

Free relative clauses: what, whoever, whichever

A free relative clause (a relative clause with no separate noun before it) refers to a thing, person, or place:

• What he said was true. (= the thing that he said)
• Choose whichever you prefer. (= any one that you prefer)
• Whoever finishes first can leave. (= any person who finishes first)

Unlike an embedded question, a free relative supplies a referent rather than reporting a question. Compare:

• I asked what she wanted. (embedded question: “What did she want?”)
• I bought what she wanted. (free relative: the thing she wanted)

Standard English normally does not use what after an expressed antecedent (the noun a relative clause refers back to): the thing that I need, not the thing what I need.

Examples in Context

English	Plain-English meaning	Note
What matters is your health.	Your health is the important thing.	Free relative as subject
I don't know whether he'll come.	I do not know if he will attend.	Embedded yes/no question
The fact that he lied is concerning.	His lie gives us cause for concern.	That-clause complementing a noun
It depends on what you want.	Your preference determines the answer.	Wh-clause after a preposition
She admitted that she had made a mistake.	She acknowledged her mistake.	That-clause as object
The main issue is that we lack reliable data.	Our lack of reliable data is the central problem.	Subject complement
Could you explain how this feature works?	Please describe the operation of this feature.	Embedded question; statement order
Nobody remembers where the documents were stored.	The storage location has been forgotten.	Embedded wh-question
Whether the proposal will pass remains unclear.	We still do not know if the proposal will pass.	Whether-clause as subject
It is surprising that nobody objected.	The absence of objections is surprising.	Extraposed that-clause
We discussed whether to postpone the launch.	We considered postponing the launch.	Whether + infinitive
Take whichever seat is available.	Choose any available seat.	Free relative with whichever
Whoever approved this overlooked a serious risk.	The person who approved this missed a risk.	Free relative referring to a person
I find working from home more productive.	In my experience, remote work is more productive.	Non-finite -ing clause as object

Common Mistakes

Using question word order inside an embedded question

• Wrong: Can you tell me where is the station?
• Right: Can you tell me where the station is?
• Why: The main clause is a question, but the embedded clause uses statement order: subject before verb.

Keeping auxiliary do from the direct question

• Wrong: I wonder why did she leave early.
• Right: I wonder why she left early.
• Why: Embedded questions do not use question-form do/does/did. The tense appears on the main verb.

Using that for an embedded question

• Wrong: I don't know that he will come. (when the meaning is uncertain)
• Right: I don't know whether/if he will come.
• Why: That introduces content presented as a statement; whether/if introduces an unresolved yes/no question. I didn't know that he would come is possible, but it means his coming was a fact unknown to me.

Using if where only whether fits naturally

• Wrong: It depends on if the payment arrives.
• Right: It depends on whether the payment arrives.
• Why: Use whether directly after a preposition. In informal speech, other versions occur, but the corrected form is the safe standard choice.

Adding an unnecessary noun before a free relative

• Wrong: The thing what matters is trust.
• Right: What matters is trust. / The thing that matters is trust.
• Why: What already means “the thing that”; do not give it a separate antecedent in standard English.

Omitting that where the sentence becomes unclear

• Awkward: The report the committee had rejected the plan shocked investors.
• Clearer: The report that the committee had rejected the plan shocked investors.
• Why: Although that is often optional after report, keeping it marks the start of a long content clause and prevents temporary misreading.

Usage Notes

In everyday speech, speakers frequently omit that after common verbs: I think you're right; she said she'd call. Formal writing retains it more often when precision or readability benefits. Neither choice is automatically “more correct”; clarity and rhythm matter.

Subject clauses beginning with what and whether are common: What worries me is the cost; Whether it works remains to be seen. Bare that-clauses as subjects are more formal, so extraposition with it is often more natural: It seems likely that demand will increase.

If is conversationally common for embedded yes/no questions, while whether is neutral to formal and highlights alternatives. Avoid treating this as a rigid formal/informal split: grammatical environment is decisive in whether to go and depending on whether.

Be careful with the term “noun clause.” A clause does not behave exactly like a concrete noun in every respect. For example, not every nominal clause can follow every preposition, and a that-clause usually needs a support noun in that position: because of the fact that it rained, not normally because of that it rained.

Beyond the Basics / Advanced Use

Mood after demands and recommendations

In formal English, a that-clause after verbs and nouns expressing demands, recommendations, or necessity may use the mandative subjunctive (the plain verb form used for a required or proposed action):

• They recommended that she apply immediately.
• It is essential that every applicant be informed.

British English also commonly uses should: They recommended that she should apply. An ordinary inflected form can change the interpretation or sound nonstandard in some varieties: They recommended that she applies may be understood as a statement about what they habitually recommend rather than the content of one recommendation.

The focused pattern What ... is ...

A free relative can create a pseudo-cleft, a structure that places focus on one element:

• What I need is a quiet afternoon.
• What surprised us was how quickly she agreed.

Agreement can vary when the focused complement is plural. What we need is more volunteers is widespread because the what-clause is grammatically singular; What we need are more volunteers also occurs, with agreement influenced by the plural complement. In edited writing, choose the version that sounds natural in context and apply it consistently.

Wh-ever forms and concession

Forms such as whoever, whatever, whichever, wherever, and however can introduce free relatives: Choose whichever fits. They can also have a concessive meaning, roughly “no matter who/what/where/how”: Whatever happens, call me. In the second use, the clause sets a circumstance rather than filling a noun position, so it is not functioning as a nominal clause.

Appositive content clauses and relative clauses

Content clauses after abstract nouns are sometimes called appositive clauses because they state the content of the noun:

• the assumption that demand will grow
• the question whether demand will grow

Test the role of the marker. In the evidence that the team presented, that stands for the evidence inside the relative clause: the team presented it. In the evidence that the method works, the that-clause expresses what the evidence supports; that is only a clause marker.

Negative raising

With verbs such as think, believe, and suppose, English often places a negative in the main clause even when its meaning applies mainly to the embedded clause:

• I don't think that she knows. often means I think that she doesn't know.

This pattern, called negative raising, is natural but not logically identical in every context. In careful argument, place the negative where it expresses the intended scope most precisely.

Practice Tips

1. Transform direct questions. Write five direct questions, then embed each after Do you know ...? or I wonder .... Check that the subject comes before the verb: Where did it happen? → I wonder where it happened.
2. Label the clause's job. In a news article, underline that-, wh-, and whether-clauses. Mark each one as subject, object, complement, or complement of a preposition. This makes long sentences easier to parse.
3. Practise contrasts, not isolated forms. Build pairs such as I know that he left (a known claim) and I don't know whether he left (an unresolved question), or I asked what she wanted (question) and I bought what she wanted (thing).

Related Concepts

• Prerequisite: Relative Clauses: where, when, whose — helps you distinguish clauses that modify a noun from clauses that themselves fill a noun-like position.