Normally there can be only one Subject, one Verb, one Object and one Complement per clause. This is not the case with Adverbials, however, which can occur an indefinite number of times in one clause. The Adverbials in the sentence below are shown in bold:
Fred had climbed /with some difficulty /into the train /on Friday night/.
This sentence could, in theory, be extended indefinitely simply by adding adverbials, but more than five per clause would perhaps be unusual. Adverbials serve a wide range of functions since they can give us information about notions such as place, movement, result, time, attitude, reason and so forth.
Adverbials more often than not consist of two or more words in a phrase as in the example above, while the term adverb is reserved for single words like then, now, yesterday, here, warmly, easily etc. To illustrate the breadth of the uses of Adverbials and adverbs further, look at the passage from Under the Volcano below – the Adverbials and adverbs are in bold and separated from each other by slashes:
The Consul sat /helplessly/ /in the bathroom/, /watching/ the insects which lay /at different angles from one another/ /on the wall/, /like ships/ /out in the roadstead/. A caterpillar started to wriggle /towards him/, /peering/ /this way and that/ /with interrogatory antennae/. A large cricket, with polished fuselage, clung /to the curtain/, /swaying/ it /slightly/ and cleaning its face /like a cat/.
As you can see, Adverbials crop up everywhere, although they may not be quite so common in everyday speech. Many of the Adverbials in the extract above tell how something was done (helplessly, peering, like a cat), or where (in the bathroom, on the wall, to the curtain); there is also one of movement, towards him. Other Adverbials can answer questions like why, when, how much, to what extent, about what, with what result as well as allowing the speaker/writer to give his/her opinion of or attitude towards something e.g. fortunately, sadly, frankly, thankfully, even more important and so on.