There are many correct answers to this question, for adverb clauses are many different things. One is that an adverb clause could also be referred to as an adverbial clause. It is a clause that is dependent but also functions as an adverb. One way to identify an adverb clause is to know that it often begins with a subordinate conjunction. This conjunction is also known as a trigger word.
There are many different types of adverb clauses. One is time, which answers the when, such as, and till. Another type is a condition, which starts with if, provided that, or lest.
