A noun clause, like other clauses, is a group of words that includeS a subject and a verb. It is a subordinate clause. As a dependent clause, it must be connected to an independent clause (main clause) to form a complete sentence. A noun clause functions as a noun, which means it can be a subject, direct object, indirect object, object of a preposition, predicate nominative, or appositive. One point to bear in mind is a noun clause is not a noun modifier.
Noun clauses usually begin with words called relative pronouns such as how, that, what, whatever, when, where, which, who, whoever, and why. The most common word among them is that.
Examples of noun clause showed here in bold. The relative pronouns used are how, that, and why.
How he can go on interrupting really annoys me.
He told me that he had shot someone.
Why he said he would not get married, nobody knows.
A noun clause has its own subject and verb. There must be a word, a relative pronoun, to connect the noun clause to the rest of the sentence. The connecting word (also called connector) comes before the subject and the verb of the noun clause. The following examples use the relative pronouns where, that, who, and when as the connecting words that begin the noun clauses. They also show that a clause can have a subject and a main verb and yet, is not an independent clause.
They know where I often fly my kites.
(The noun clause is where I often fly my kites, with I as the subject of the noun clause, and fly as the verb. )
He told us that a spider has eight legs.
The police were investigating who the serial killer was..
I don't know when the birds built their nest in the roof.
Noun clauses can be the subject, direct object, indirect object, object of preposition, object of verbal noun (gerund) or complement. The noun clauses in the following examples are in bold.
That the brothers are triplets is amazing. (Subject)
Everyone of us knows what songs she often sings. (Direct object)
The rescuers who were all volunteers carried out successful searches for survivors. (Indirect object)
The book is about where the dinosaurs laid their eggs. (Object of preposition)
Arguing which colour is the most beautiful is not going to help anyone. (Object of gerund)
He is what we would call a misogynist. (Predicate nominative/Complement)
Converting a question into a noun clause.
Question: When did we get married?
(To turn the question into a noun clause, a main clause with a main verb is needed to form a complete sentence.)
Sentence with noun clause: I have forgotten when we got married.
(Main clause is I have forgotten, and noun clause is when we got married. Not: I have forgotten when did we get married.)
The relative pronouns if and whether can be used to change a question – usually a yes/no question – into a noun clause.
Do you all know where my pencil is?
I'm asking if you all know where my pencil is.
(Main clause: I'm asking. Noun clause: if you all know where my pencil is)
Do you not like being here?
You can go if you do not like being here.
Did he drink from your glass or mine by mistake?
Ask him whether he drank from your glass or mine by mistake.
(Main clause: Ask him. Noun clause: whether he drank from your glass or mine by mistake)
Subjunctive in noun clauses
Subjunctive verbs are used in sentences to express or stress wishes, importance, urgency, etc. A subjunctive verb usually appears in a noun clause beginning with that, and it uses the simple form of a verb that does not have the present, past or future forms. The subjunctive verb is neither singular nor plural.
The father advised that she not go to the cinema alone..
His mother suggested that he see see a doctor.
The kidnappers demand that the company's Manager pay for our release.
We insisted that the other party honour the terms of the agreement.
The villagers recommended that the driver take the other route which was shorter.
It is important that everyone be told the truth.