2. noun clauses

# videos: on the following subpages:
a. noun clauses and relative adverbs 

Noun clauses work as "nouns," and are connected to main/independent clauses via the following relative adverbs; hence, noun clauses are sometimes also called relative adverb clauses.
1) that
2) if, whether
3) wh- words: how, what, when, where, which, who, whom, whose, why
4) wh- ever words: however, whatever, whenever, wherever, whichever, whoever, whomever