Answer:
There aren't any italicized noun clauses.
Explanation:
However, it is possible to explain something:
The subject is the doer of the action, in this case, a lecture.
The direct object is directly affected by the main verb, what the children.
The predicate noun is a noun or a phrase noun that renames the subject of a sentence after to be in any of its forms (present, past, participle), what the children wanted to hear.
The object of preposition is the noun or pronoun ruled by a preposition, cleanliness.