An adverbial clause is a dependent clause that functions as an adverb. That is, the entire clause modifies a verb, an adjective, or another adverb. As with all clauses, it contains a subject and predicate, though the subject as well as the (predicate) verb may sometimes be omitted and implied (see below).
An adverbial clause is fronted by a subordinating conjunction--sometimes called a trigger word. (In the examples below the adverbial clause is italicized and the subordinating conjunction is bolded.)
According to Sidney Greenbaum and Randolph Quirk, adverbial clauses function mainly as adjuncts or disjuncts, which parts also perform in a sentence as adverbial phrases or as adverbial prepositional phrases (Greenbaum and Quirk, 1990). Unlike clauses, phrases do not contain a subject and predicate; they are contrasted here:
Adverbial clauses are divided into several groups according to the actions or senses of their conjunctions:
|Type of clause||Common conjunctions||Function||Example|
|time||Conjunctions answering the question "when?", such as: when, before, after, since, while, as, as long as, till, until, etc.;||These clauses:
Say when something happens by referring to a period or point of time, or to another event.
|Her goldfish died when she was young.
He came after night had fallen.
We barely had gotten there when mighty Casey struck out.
He told us his adventures in Arctic as we went along.
|condition||if, unless, lest, provided that||Talk about a possible or counterfactual situation and its consequences.||If they lose weight during an illness, they soon regain it afterwards.|
|purpose||in order to, so that, in order that, in case||Indicate the purpose of an action.||They had to take some of his land so that they could extend the churchyard.|
|reason||because, since, as, given||Indicate the reason for something.||I couldn't feel anger against him because I liked him too much.|
|concession||although, though, while||Make two statements, one of which contrasts with the other or makes it seem surprising.||I used to read a lot, though I don't have much time for books now.|
|place||Answering the question "where?": where, wherever, anywhere, everywhere, etc.||Talk about the location or position of something.||He said he was happy where he was.|
|comparison||as...as, than, as||State comparison of a skill, size or amount, etc.||Johan can speak English as fluently as his teacher.
She is a better cook than I.
|manner||Answering the question, "how"?: as, like||Talk about someone's behavior or the way something is done.||I was never allowed to do things as I wanted to do.
He spent a lot of money as if he was very rich.
|results||so...that, such...that||Indicate the result(s) of an act or event.||My suitcase had become so damaged that the lid would not stay closed.|