Noun clauses are dependent clauses that act as nouns. A noun clause may be used as the subject, direct object, indirect object, or complement in a sentence. The word that can also be used to convert whole clauses into forms that can be used as the subjects or objects of sentences.
Studies in emergency rooms in Wilmington, Del., and Atlanta, have found
that sensitization to cockroaches is an important risk factor for
--"Roach Wars," Scientific American