An adverbial clause is a dependent clause that functions as an adverb. That is, the entire clause modifies a separate element within a sentence. As with all clauses, it contains a subject and predicate, though the subject as well as the (predicate) verb are omitted and implied if the clause is reduced to an adverbial phrase as discussed below.
Adverbial clause versus adverbial phrase
An adverbial clause begins with a subordinating conjunction—sometimes called a trigger word. In the examples below, the adverbial clause is italicized and the subordinating conjunction is bolded:
- Mary, the aspiring actress, became upset as soon as she saw the casting list.
- (subject: she; predicate: saw the casting list; the clause modifies the verb became)
- Peter, the drama teacher, met with Mary after she calmed down.
- (explicit subject: she; predicate: calmed down; predicate (verb): calmed; the clause modifies the verb met)
- We left before the speeches ended.
- (adverbial clause; contains subject and predicate)
According to Sidney Greenbaum and Randolph Quirk (Greenbaum and Quirk, 1990), adverbial clauses function mainly as adverbial adjuncts or disjuncts but differ in syntax from adverbial phrases and adverbial prepositional phrases, as indicated below.
Unlike adverbial clauses, adverbial phrases contain neither an explicit subject nor a predicate. In the examples below, the adverbial phrase is italicized and the adposition is bolded:
- Mary, the aspiring actress, became upset as one of the casting list rejects.
- Peter, the drama teacher, met with Mary after seeing her disappointment.
- We left before the speeches.
Adverbial clauses are divided into several groups according to the actions or senses of their conjunctions:
|Type of clause||Common conjunctions||Function||Example|
|adverb clause of 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.
|adverb clause of 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.|
|adverb clause of 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.|
|adverb clause of reason||because, since, as, given||Indicate the reason for something.||I couldn't feel anger against him because I liked him too much.|
|adverb clause of concession ( contrast)||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.|
|adverb clause of 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.|
|adverb clause of comparison||as...as, than, as||State comparison of a skill, size or amount, etc.||Johan can speak English as fluently as his teacher can.
She is a better cook than I am.
|adverb clause of 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.
|adverb clause of 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.|
- Greenbaum, Sidney & Quirk, Randolph. A Student's Grammar of the English Language. Hong Kong: Longman Group (FE) Ltd, 1990.
- Sinclair, John (editor-in-chief). Collins Cobuild English Grammar. London and Glasgow: William Collins Sons & Co ltd, 1990.