A noun clause is a subordinate clause that functions as a noun. Because it functions as a noun, this clause can be a subject, direct object, indirect object, object of a preposition, predicate nominative, or appositive.
- I told him that he had been selected. (The noun clause “that he had been selected” functions as a direct object.)
- Where the candy bar is hidden remains a mystery. (The noun clause “where the candy bar is hidden” functions as the subject of the sentence.)
- Pay attention to what I say. (The noun clause what I say functions as the object of the preposition to.)
- The news that he is alive has been confirmed. (The noun clause that he is alive is in apposition to the noun news.)