Noun Clauses

What is a noun clause?

A noun clause is a clause that does the job of a noun. Wherever you could put a single noun (or a noun phrase), you can put a whole noun clause.

The answer surprised me. (noun phrase as subject) What he said surprised me. (noun clause as subject)

I know the truth. (noun phrase as object) I know that he lied. (noun clause as object)

The clause has its own subject and verb, but the whole package functions as a single noun-shaped unit inside the bigger sentence.

Function in sentence	Example noun phrase	Equivalent noun clause
Subject	Honesty matters.	Whether he is honest matters.
Object	I know the truth.	I know that he is honest.
Subject complement	The truth is honesty.	The truth is that he is honest.
Object of preposition	I'm tired of lies.	I'm tired of how he lies.

Noun clauses are usually introduced by one of a small set of words: that, whether, if, what, who, where, when, why, how.

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that-Clauses

A that-clause reports a fact, idea, or belief. The clause is introduced by the word that, followed by a normal subject + verb.

I think **that he is right**.

The fact **that she lied** is troubling.

It's true **that he resigned**.

We agreed **that the meeting would be postponed**.

Dropping that

In informal English, that is often omitted after common reporting verbs (think, say, believe, know, feel):

I think he is right. (= I think that he is right.)

She said she'd come.

But you should keep that when:

• the clause is the subject of a sentence: That he lied is shocking.
• the clause is introduced by the fact that: The fact that he lied is shocking.
• the verb is followed by an indirect object: He told me **that** he was leaving. (omitting that here is awkward)
• in formal writing (essays, reports).

It + that-clause: avoiding heavy subjects

A noun clause as a subject can sound heavy or awkward. English usually rephrases with dummy it at the front and the clause moved to the end.

Heavy	Natural
That he passed the exam surprised everyone.	It surprised everyone that he passed the exam.
That she didn't come was disappointing.	It was disappointing that she didn't come.
That smoking is harmful is well known.	It is well known that smoking is harmful.

This it … that structure is one of the most common patterns in academic English.

the fact that

When you want to treat a fact as a noun (especially as the subject), introduce it with the fact that:

The fact that he lied changes everything.

We can't ignore the fact that costs are rising.

Despite the fact that it was raining, we went out.

This makes the clause function more clearly as a noun phrase — useful in formal writing and after prepositions (despite, because of, due to) which can’t take a that-clause directly.

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whether and if: Yes/No Noun Clauses

When the noun clause expresses a yes/no question or a choice, use whether or if.

I don't know **whether he will come**.

She asked me **whether I had eaten**.

I'm not sure **if this is correct**.

Tell me **if you need help**.

whether vs if

The two are usually interchangeable, but whether is more flexible.

Position	Use whether?	Use if?
After a verb (object)	yes	yes
As the subject	yes	no
After a preposition	yes	no
Before or not (adjacent)	yes	no
Before a to-infinitive	yes	no

When only whether works:

Whether he comes or not is up to him. (subject)

We talked about whether to invite him. (after preposition)

I don't know whether or not to go. (adjacent or not)

I don't know whether to go. (before infinitive)

When if is fine:

I don't know if he's coming. (object — both if and whether work)

Could you tell me if the train has left? (object)

Rule of thumb: in formal writing, default to whether. In speech, if is everywhere.

or not

You can attach or not to either word, but the position matters.

I don't know whether or not he is coming. (adjacent — fine)

I don't know if or not he is coming. (not allowed)

I don't know if he is coming or not. (at the end — both whether and if work)

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wh- Noun Clauses (Embedded Questions)

When a wh-question becomes part of a bigger sentence, it transforms into a noun clause. The most important change is word order.

A direct question uses inverted word order (verb before subject) and ends with a question mark:

Where does she live?

What did he say?

How long has he been here?

When that question becomes a noun clause inside a longer sentence, the word order returns to normal statement order (subject before verb), and the question mark disappears (unless the whole sentence is a question).

Direct question	Embedded noun clause
Where does she live?	I don't know **where she lives**.
What did he say?	Tell me **what he said**.
How long has he been here?	I'm curious **how long he has been here**.
Why is she late?	Nobody knows **why she is late**.
When will the train arrive?	Can you tell me **when the train will arrive**?

Notice three changes from question to noun clause:

1. No auxiliary do/does/did — the original main verb takes its tense back: does she live → she lives.
2. Subject before verb — where she lives, not where does she live.
3. No question mark unless the entire outer sentence is a question.

As the subject of a sentence

What he said was offensive.

How they got in is still a mystery.

Why she left doesn’t matter.

After prepositions

We disagreed about **what to do next**.

I'm worried about **how she will react**.

This depends on **whether the budget is approved**.

Polite indirect questions

This pattern is especially common when softening a question:

Direct	Polite (embedded)
Where is the bathroom?	Could you tell me **where the bathroom is**?
What time does it close?	Do you know **what time it closes**?
Has the train left?	I was wondering **if the train has left**.

The whole sentence is still a question (and ends with ?), but the embedded clause inside follows statement word order.

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wh- + to-infinitive

Many wh-noun clauses can be reduced to a wh-word + to-infinitive when the subject is the same as in the main clause and the meaning involves possibility, advice, or choice.

I don't know **what to do**. (= what I should do)

Can you tell me **how to fix this**?

She's deciding **whether to apply**.

We were unsure **where to meet**.

Tell me **when to start**.

Note: if cannot be used in this construction — only whether. Tell me if to go. is wrong; Tell me whether to go. is correct.

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Common Mistakes

Mistake	Better	Why
Tell me where does she live.	Tell me where she lives.	Embedded questions use statement word order — no auxiliary do/does.
I don't know what did he say.	I don't know what he said.	Same: drop the did, restore the past tense on the verb.
I'm not sure if or not he is coming.	I'm not sure whether or not he is coming.	if cannot sit directly next to or not.
Whether the meeting will happen depend on him.	Whether the meeting will happen depends on him.	A noun clause is singular — the verb takes a singular form.
Tell me if to go.	Tell me whether to go.	Only whether (not if) precedes a to-infinitive.
Despite that he was tired, he kept working.	Despite the fact that he was tired, he kept working.	A preposition (despite) can’t take a that-clause directly; insert the fact that.
That he passed the exam surprised everyone. (heavy)	It surprised everyone that he passed the exam.	Heavy noun-clause subjects sound natural with dummy it.
She told me that did you call.	She told me that you called.	Don’t keep question word order in a that-clause.
Can you tell me where is the post office?	Can you tell me where the post office is?	The outer sentence is a question; the embedded clause is not — keep statement word order inside.

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Quick-Reference Cheat Sheet

If you want to express…	Use…	Example
A reported fact or belief	that + clause	I believe (that) he's right.
A yes/no choice	whether / if + clause	Tell me if you're coming.
A wh- question, embedded	wh-word + statement order	I don't know where she lives.
A heavy that-clause subject	It + verb + that-clause	It's clear that he won.
A fact treated as a noun	the fact that + clause	The fact that he lied matters.
A wh- noun clause with same subject	wh-word + to-infinitive	I don't know what to say.

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Practice: Exercises

1 / 15

Which sentence contains a noun clause as the subject?

AHe said the answer.BWhat he said surprised me.CI heard him speak.DShe told me a story.

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Summary

A noun clause does the work of a noun — subject, object, complement, or object of a preposition.

• that-clause: for facts and beliefs. Drop that casually; keep it in formal writing and after the fact.
• whether / if: for yes/no questions. whether is more flexible — it can be a subject, follow a preposition, sit next to or not, and precede a to-infinitive.
• wh-clauses: when a wh-question becomes embedded, drop the auxiliary and restore statement word order: Where does she live? → I don’t know where she lives.
• Heavy subjects: prefer It + verb + that-clause over a front-loaded that-clause.
• Prepositions can’t take that-clauses — use the fact that to bridge the gap.
• wh- + to-infinitive (what to do, where to go) reduces a noun clause when the subject is shared.

The single biggest test point at B2 is word order inside an embedded question — it always reverts to subject + verb, no matter how the outer sentence behaves.