An adverbial clause (or an adverb clause) is a group of words which
plays the role of an adverb. (Like all clauses, an adverbial clause will
contain a subject and a verb.)
The clause can modify
verbs, adverbs and adjectives by telling when, where, why, how, how much
and under what condition. They begin with a subordinating conjunction (such as after, if, because and although) and they contain a subject and a predicate.
Here are some examples of adverb clauses, which are bold in letters ....
Whether you like it or not, you have to go to bed now. She likes the red car more than her husband does. If you pay your bills, you will have a good credit score. Unless you run fast, you will miss the bus.