The clause which works as a noun in a sentence is called a noun clause. A noun clause can be connected by the following connectives,
(i) that (expressed or understood).
(ii) interrogative pronoun (who, what, which, whom, whatever, whichever, etc.
(iii) interrogative adverb (how, where, why, if, etc.
The noun clause's position in a sentence
Like any noun, a noun clause may be used as
(i) a subject,
(ii) an object, or
(iii) a complement in a sentence.
(i) A subject to a verb: When a noun clause acts as a subject to a verb, it usually starts with the words like that, what, how, when, why, whether, etc.
In such kinds of sentences, the part before the be verb/ linking verb (am, is, are, was, were) is now: clause and the rest part i.e. from being verb/linking verb to the last is the principal clause. Structure : Noun Clause + be verb/linking verb + principal clause.
Noun clause principal clause
(1) Why he has done this is not clear.
(2) When he will leave the country is not certain.
(2) An object to a verb: When a noun clause acts as an object to a verb, it usually starts with that,
what, when, where, who, why, how, and if. A noun clause often acts as an object of a transitive verb.
Structure: Principal clause +noun clause (as object)
Examples :
I know that he has done the work
principal clause Noun clause (as object)
I forgot who told me this I know where he lives.
(3) Complement to an object:
When a noun clause works as a complement to an object, it generally starts with that, what, why, how,
whatever, if, etc. In this case from the beginning of the sentence to personal object is the principal
clause and the rest part is a noun clause.
Structure : Subject + verb + object + noun clause as complement to object.
Examples : (1) I told him what he wanted to know from me.
(2) You can give me what I want.
(3) The magician can show you whatever you like.
(4) An object to a preposition.
When a noun clause works as an object to a preposition, it generally starts with (that and WH words
What, where, who, how, etc.)
Structure: Principal clause + preposition + noun clause (as object to a preposition)
Sometimes preposition and the noun clause sit before the principal clause.
Examples:
(1) It depends on what you mean. Principal clause noun clause
(2) He has come from where I worked.
(3) I do not know who did it.
(5) In apposition to noun/pronoun: When noun clause acts as an apposition, it usually starts with that. In this case noun clause as an apposition sits after the noun facts, truth, explanation,
rumor, news, belief, statement, report, etc.
Structure : Subject* verb +noun + noun clause as an apposition.
Examples:
(1) There is a rumor that he has left the country.
(2) You must face the fact that you have spent all your money,
