Subject
* That the earth is round is a well-established fact.
* What she said surprised everyone.
Predicate Nominative
* The biggest problem is that we don't have enough time.
* My biggest fear is that I might fail the exam.
Direct Object
* I know that you are telling the truth.
* The scientist discovered how the virus spreads.
Indirect Object
* She told whoever was listening the secret.
* The teacher gave whoever finished first a prize.
Object of the Participle
* Excited that the game was about to start, the fans cheered.
* Worried that they might be late, the friends rushed.
Object of a Gerund
* I enjoy reading books that are about history.
* He hates doing work that is boring.
Appositive
* The idea, that we should go on a trip, was met with enthusiasm.
* The announcement, that the school would be closed, came as a surprise.
Object of an Infinitive
* I want to know why you are so late.
* The students planned how they would celebrate the victory.
Important Note: Noun clauses often begin with words like "that", "what", "who", "where", "when", "why", or "how".