An adverbial is an adverb, adverbial phrase or adverbial clause which gives us additional information about e.g. the time, place, or manner of the action which is described in the rest of the sentence:
From these examples, you can see that the most common position for adverbials is at the end of the sentence Place adverbials (here in this house) come before time adverbials (for over twenty years). Manner adverbials (peacefully) come before place adverbials (in our beds).
They do not always follow this pattern. This applies particularly to adverbial clauses. In the above example we could begin with the adverbial clause, if it was important to highlight it at this stage in the discourse:
Thus, adverbials answer questions such as:
Where did you arrange to meet him? ~
Why did you arrange to meet him there?
How long did you wait for him?
When did you first meet him?
Note from the above examples that adverbs of frequency are often placed in mid-position in the sentence, as well as at end-position. Placing them before the subject is sometimes also possible:
A wide variety of different conjunctions are used to initiate adverbial clauses which function as the adverbial part of a main clause. Some of the most common are listed below: