Noun Clause

A noun clause has a subject and verb and functions as a noun. A noun clause is a dependent clause or subordinate clause and is not a complete sentence. It must be connected to an independent clause. Noun clauses usually begin with how, that, what, whatever, when, where, which, who, whoever, orwhy.

• A noun clause is a dependent clause

EXAMPLE: He knows where I live.
This complete sentence has an independent clause with the main subject(He) and verb (knows). Where I live is a dependent clause called a noun clause connected to an independent clause (He knows).

• A noun clause has its own subject and verb.

EXAMPLE: He knows where I live.
In this example, the noun clause is where I live. I is the subject of the noun clause; live is the verb of the noun clause.

• A noun clause can be used as a subject.

EXAMPLE: What she sang was a Hungarian folk song.
What she sang is a noun clause, and is also the subject of the sentence. The noun clause has its own subject she and the verb sang.

• A noun clause can be used as an object.

EXAMPLE: I saw what he did.
The noun clause is what he did. It is used as the object of the verb saw.

• A noun clause can be used as the object of a preposition.

EXAMPLE: I always paid attention to what my father said.
In the example, what my father said is a noun clause. It is used as the objectof the preposition to.

• A noun clause can start with a question word.

EXAMPLE: I don't know where my bunch of keys is.
The noun clause is where my bunch of keys is.

• A noun clause can begin with if or whether;.

EXAMPLE: I don't know whether or not she will accept my proposal of marriage.
The noun clause: whether or not she will accept my proposal of marriage.

• We can begin a noun clause with that.

EXAMPLE: My mother-in-law insists that the world is oval.
That the world is oval is the noun clause. 

Subjunctive in Noun Clauses
We use subjunctive verbs in sentences to express or stress wishes,importance or urgency. A subjunctive verb is used in noun clauses beginning with that. It uses the simple form of a verb, and does not have present,past, or future forms. It is neither singular nor plural.

EXAMPLE:
The leader demands that we be early for the trip.
We insisted that he honour the terms of the agreement.
The father recommended that she not go to the cinema alone.
It is important that everyone be told the truth.
His mother suggested that he see/should see a doctor.

Noun clause used as an object  He said something.         What did he say?  S V O  He said that he was sick.  Noun clause used as a subject  Something is your business.  What is your business?  S V  Whatever you do is your business.    Someone is still in the cafeteria.  Who is in the cafeteria?  S V  Whoever ate my lunch is still in the cafeteria.

Subjunctive in Noun Clauses
We use subjunctive verbs in sentences to express or stress wishes,importance or urgency. A subjunctive verb is used in noun clauses beginning with that. It uses the simple form of a verb, and does not have present,past, or future forms. It is neither singular nor plural.

EXAMPLE:
The leader demands that we be early for the trip.
We insisted that he honour the terms of the agreement.
The father recommended that she not go to the cinema alone.
It is important that everyone be told the truth.
His mother suggested that he see/should see a doctor.

http://www.myenglishgrammar.com/lesson-17-clauses/4-noun-clause.html

http://www.eslgold.com/grammar/noun_clauses.html