Adverb clauses in English grammar are subordinate or dependent clauses that consist of a subordinating conjunction followed by a clause and that perform adverbial grammatical functions.
Adverb clause is a grammatical form.
All adverb clauses are finite. Finite clauses contain conjugated verbs functioning as predicates.
Brinton, Laurel J. & Donna M. Brinton. 2010. The linguistic structure of Modern English, 2nd edn. Amsterdam: John Benjamins Publishing Company.
Hopper, Paul J. 1999. A short course in grammar. New York: W. W. Norton & Company.
Huddleston, Rodney. 1984. Introduction to the grammar of English. Cambridge: Cambridge University Press.